HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news

Cheap flights from Baltimore to Bismarck (BWI - BIS) from $256

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/16. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
BWI — BIS
jun. 4 — jun. 111
From?
To?
mar. 6/4
mar. 6/11
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Cheap flight deals from Baltimore to Bismarck

Discover tips and strategies to find the most affordable flight options for your journey from Baltimore (BWI) to Bismarck (BIS). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated mayo 30, 2024.

Popular in

December

Cheapest in

February

Average price

$427

Round-trip from

$340
High demand for flights, 44% potential price rise
Search Deals
Best time to find cheap flights, 52% potential price drop
Search Deals
Average for round-trip flights in May 2024
Search Deals
From Baltimore/Washington to Bismarck
Search Deals

What is the cheapest day to fly round-trip from Baltimore to Bismarck?

Saturday flights are found to be more expensive to fly from Baltimore to Bismarck. This shouldn’t discourage you from searching, as you can still find great deals by being flexible with your options. Use our search form to find deals on tickets to Bismarck.

What is the cheapest month to fly from Baltimore to Bismarck?

Our data shows that January tends to be the cheapest month to fly to Bismarck from Baltimore. Users have commonly found prices around $587 for the month, but tickets can be as low as $367. Due to multiple factors, prepare for potentially higher prices in December.

What is the cheapest time of day to fly from BWI to BIS?

One of the essential ways to save on airfare from Baltimore to Bismarck is to remain as flexible as possible. Flights that are in the afternoon tend to be the most expensive. A flight at noon could potentially save you up to 31% on airfare.

Cheap Delta flights from Baltimore to Bismarck

Explore cheap flight options specifically provided by Delta for the route between Baltimore and Bismarck. Find affordable fares and compare prices with other airlines to secure the best deal for your journey. Over the last 7 days, Cheapflights users made 2,784,634 searches. Data last updated mayo 30, 2024.
Consider these cheap Delta flights we've found departing from Baltimore to Bismarck. It's recommended that users confirm their flight details before booking.
vie. 8/167:02 pmBWI - BIS
1 stop6h 22mDelta
dom. 8/185:00 amBIS - BWI
1 stop4h 30mDelta
Deal found 5/29$256
sáb. 8/105:34 pmBWI - BIS
2 stops6h 56mDelta
mar. 8/135:00 amBIS - BWI
2 stops9h 34mDelta
Deal found 5/29$266
mar. 6/186:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/223:50 pmBIS - BWI
1 stop7h 00mDelta
Deal found 5/29$274
mié. 8/1411:35 amBWI - BIS
1 stop7h 51mDelta
mié. 8/215:00 amBIS - BWI
2 stops11h 05mDelta
Deal found 5/29$279
sáb. 8/105:34 pmBWI - BIS
2 stops6h 56mDelta
mar. 8/135:00 amBIS - BWI
1 stop4h 30mDelta
Deal found 5/29$306
mié. 8/149:59 amBWI - BIS
2 stops10h 47mDelta
mié. 8/217:50 amBIS - BWI
2 stops8h 15mDelta
Deal found 5/29$311
lun. 6/106:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/155:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/29$319
lun. 6/106:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/153:50 pmBIS - BWI
2 stops7h 53mDelta
Deal found 5/29$324
sáb. 8/103:00 pmBWI - BIS
1 stop5h 46mDelta
mar. 8/135:00 amBIS - BWI
1 stop4h 30mDelta
Deal found 5/29$346

Cheap United Airlines flights from Baltimore to Bismarck

Explore cheap flight options specifically provided by United Airlines for the route between Baltimore and Bismarck. Find affordable fares and compare prices with other airlines to secure the best deal for your journey. Over the last 7 days, Cheapflights users made 2,784,634 searches. Data last updated mayo 30, 2024.
Have a look at some of the cheapest available United Airlines flights departing from Baltimore and landing in Bismarck. Make sure to examine the flight information before completing your reservation.
vie. 8/166:30 amBWI - BIS
2 stops15h 11mUnited Airlines
dom. 8/185:27 pmBIS - BWI
2 stops15h 30mUnited Airlines
Deal found 5/29$532
dom. 7/2110:05 amBWI - BIS
1 stop7h 26mUnited Airlines
mar. 7/231:35 pmBIS - BWI
1 stop8h 26mUnited Airlines
Deal found 5/29$845
dom. 7/218:07 amBWI - BIS
1 stop9h 24mUnited Airlines
mié. 7/241:35 pmBIS - BWI
1 stop8h 26mUnited Airlines
Deal found 5/29$876

Cheap Baltimore to Bismarck flights in May & June 2024

Find cheap flight options from Baltimore to Bismarck specifically for the months of May and June 2024. Explore affordable fares based on user searches. Over the last 7 days, Cheapflights users made 2,784,634 searches. Prices were last updated on mayo 30, 2024.
Scroll through some of the best deals on flights from Baltimore to Bismarck in 2024. Check back in a little while for more flight options.
mar. 6/186:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/223:50 pmBIS - BWI
1 stop7h 00mDelta
Deal found 5/29$274
lun. 6/106:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/155:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/29$319
lun. 6/106:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/153:50 pmBIS - BWI
2 stops7h 53mDelta
Deal found 5/29$324
lun. 6/105:13 pmBWI - BIS
2 stops8h 11mDelta
sáb. 6/153:50 pmBIS - BWI
2 stops7h 53mDelta
Deal found 5/29$356
mié. 5/295:52 pmBWI - BIS
1 stop6h 22mDelta
lun. 6/35:00 amBIS - BWI
1 stop4h 59mDelta
Deal found 5/29$400
vie. 6/146:33 pmBWI - BIS
1 stop6h 51mDelta
lun. 6/175:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/29$405
mié. 5/295:52 pmBWI - BIS
1 stop6h 22mDelta
lun. 6/312:38 pmBIS - BWI
2 stops9h 28mDelta
Deal found 5/29$484
mar. 6/186:05 amBWI - BIS
2 stops6h 34mDelta
sáb. 6/223:50 pmBIS - BWI
1 stop7h 00mDelta
Deal found 5/29$522
vie. 6/141:19 pmBWI - BIS
2 stops10h 26mAmerican Airlines
lun. 6/173:07 pmBIS - BWI
1 stop7h 20mAmerican Airlines
Deal found 5/29$616

Baltimore to Bismarck 2024 flight deals

Discover exclusive flight deals for travel between Baltimore and Bismarck in 2024. Find excellent offers based on user searches. Over the last 7 days, Cheapflights users made 2,784,634 searches. Data last updated mayo 30, 2024.
Scroll through some of the best deals on flights from Baltimore to Bismarck in 2024. Check back in a little while for more flight options.
vie. 8/167:02 pmBWI - BIS
1 stop6h 22mDelta
dom. 8/185:00 amBIS - BWI
1 stop4h 30mDelta
Deal found 5/29$256
sáb. 8/105:34 pmBWI - BIS
2 stops6h 56mDelta
mar. 8/135:00 amBIS - BWI
2 stops9h 34mDelta
Deal found 5/29$266
mar. 6/186:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/223:50 pmBIS - BWI
1 stop7h 00mDelta
Deal found 5/29$274
mié. 8/1411:35 amBWI - BIS
1 stop7h 51mDelta
mié. 8/215:00 amBIS - BWI
2 stops11h 05mDelta
Deal found 5/29$279
sáb. 8/105:34 pmBWI - BIS
2 stops6h 56mDelta
mar. 8/135:00 amBIS - BWI
1 stop4h 30mDelta
Deal found 5/29$306
mié. 8/149:59 amBWI - BIS
2 stops10h 47mDelta
mié. 8/217:50 amBIS - BWI
2 stops8h 15mDelta
Deal found 5/29$311
lun. 6/106:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/155:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/29$319
lun. 6/106:33 pmBWI - BIS
1 stop6h 51mDelta
sáb. 6/153:50 pmBIS - BWI
2 stops7h 53mDelta
Deal found 5/29$324
sáb. 8/103:00 pmBWI - BIS
1 stop5h 46mDelta
mar. 8/135:00 amBIS - BWI
1 stop4h 30mDelta
Deal found 5/29$346

Baltimore to Bismarck flights leaving soon

Find last-minute flight options from Baltimore to Bismarck for spontaneous travel. Discover available flights and compare prices based on user searches. Secure great deals and offers for spontaneous trips with quick booking options. Over the last 7 days, Cheapflights users made 2,784,634 searches. Data last updated mayo 30, 2024.
Have a look at some of the flights available from Baltimore to Bismarck departing last-minute. Users should examine the flight details to ensure there are no surprises.
mié. 6/55:52 pmBWI - BIS
1 stop6h 22mDelta
jue. 6/135:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/30$646
vie. 6/711:37 amBWI - BIS
1 stop7h 46mDelta
jue. 6/135:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/30$705
mié. 6/55:52 pmBWI - BIS
1 stop6h 22mDelta
mié. 6/125:39 pmBIS - BWI
1 stop5h 11mDelta
Deal found 5/30$809
jue. 6/65:52 pmBWI - BIS
1 stop6h 27mDelta
jue. 6/135:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/30$846
vie. 6/711:37 amBWI - BIS
1 stop7h 46mDelta
mié. 6/125:39 pmBIS - BWI
1 stop5h 11mDelta
Deal found 5/30$868
jue. 6/66:10 amBWI - BIS
2 stops6h 35mDelta
jue. 6/135:00 amBIS - BWI
1 stop4h 32mDelta
Deal found 5/30$920
jue. 6/66:00 amBWI - BIS
1 stop6h 45mDelta
mié. 6/125:39 pmBIS - BWI
1 stop5h 11mDelta
Deal found 5/30$1,028
mié. 6/55:52 pmBWI - BIS
1 stop6h 22mDelta
mié. 6/125:39 pmBIS - BWI
2 stops14h 06mDelta
Deal found 5/30$1,040
jue. 6/66:10 amBWI - BIS
2 stops6h 35mDelta
mié. 6/125:39 pmBIS - BWI
1 stop5h 11mDelta
Deal found 5/30$1,083

Find flights from Baltimore to Bismarck within your budget

Customize your flight search to find flights from Baltimore to Bismarck that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,784,634 searches. Data last updated mayo 30, 2024.

Fly from

Any airport

Fly to

Any airport

Budget

$256 - $616

Route

Depart

Return

Price

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

vie. 8/16

1 stop6h 22m

Bismarck

dom. 8/18

1 stop4h 30m

$256

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

sáb. 8/10

2 stops6h 56m

Bismarck

mar. 8/13

2 stops9h 34m

$266

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

mar. 6/18

1 stop6h 51m

Bismarck

sáb. 6/22

1 stop7h 00m

$274

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

mié. 8/14

1 stop7h 51m

Bismarck

mié. 8/21

2 stops11h 05m

$279

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

sáb. 8/10

2 stops6h 56m

Bismarck

mar. 8/13

1 stop4h 30m

$306

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

mié. 8/14

2 stops10h 47m

Bismarck

mié. 8/21

2 stops8h 15m

$311

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

mar. 7/23

2 stops22h 03m

Bismarck

vie. 7/26

2 stops17h 58m

$453

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

vie. 8/16

2 stops15h 11m

Bismarck

dom. 8/18

2 stops15h 30m

$532

Baltimore/WashingtonBismarck

BWI - BIS

BWIBIS

Baltimore/Washington

vie. 6/14

2 stops10h 26m

Bismarck

lun. 6/17

1 stop7h 20m

$616

Flights are sorted by cheapest first

Deals found on 5/29

What is the cheapest day to fly from Baltimore to Bismarck?

Use this chart to determine the cheapest time to fly round-trip from Baltimore to Bismarck. Price data was last updated on May 26, 2024.
Morning
Noon
Afternoon
Evening
All times are departure.
Travelers seeking maximum savings on their Baltimore to Bismarck flight should consider departing on Monday afternoons when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.
Search Deals

Best time to book a flight from Baltimore to Bismarck

Have a flexible travel schedule? Discover the best time to fly to Bismarck from Baltimore with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Temperature and rainfall in Bismarck by month

Plan your trip to Bismarck by taking into account the average temperature and rainfall totals by month.

BIS

Temperature

12.2 - 71.6 °F

Reviews of airlines servicing Bismarck

Get insights into the airlines that provide service to Bismarck. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Bismarck. Reviews last updated mayo 30, 2024.
Read reviews from past customers who have flown Delta, United Airlines and American Airlines from Baltimore to Bismarck. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
10,457 reviews
Check prices

Food

7.4

Overall

8.0

Crew

8.6

Comfort

7.9

Boarding

8.2

Entertainment

8.0

Reviews

1 / 10

When I was going to board, one of the staff members told me that I could not board with my passport bag because it was tree items and I would need to check a bag. This was so stupid ! The bag was small. So I had to put my things in my pockets, put the funny bag inside the other bag. Then go throw it. Then in the plane put everything back again in my funny bag.

Delta
8.0
Very good
10,457 reviews
Delta
8.0
Very good
10,457 reviews
Check prices

Food

7.4

Overall

8.0

Crew

8.6

Comfort

7.9

Boarding

8.2

Entertainment

8.0

Reviews

1 / 10

When I was going to board, one of the staff members told me that I could not board with my passport bag because it was tree items and I would need to check a bag. This was so stupid ! The bag was small. So I had to put my things in my pockets, put the funny bag inside the other bag. Then go throw it. Then in the plane put everything back again in my funny bag.

United Airlines
7.4
Good
10,777 reviews
Delta
8.0
Very good
10,457 reviews
Check prices

Food

7.4

Overall

8.0

Crew

8.6

Comfort

7.9

Boarding

8.2

Entertainment

8.0

Reviews

1 / 10

When I was going to board, one of the staff members told me that I could not board with my passport bag because it was tree items and I would need to check a bag. This was so stupid ! The bag was small. So I had to put my things in my pockets, put the funny bag inside the other bag. Then go throw it. Then in the plane put everything back again in my funny bag.

American Airlines
7.3
Good
14,284 reviews
Delta
8.0
Very good
10,457 reviews
Check prices

Food

7.4

Overall

8.0

Crew

8.6

Comfort

7.9

Boarding

8.2

Entertainment

8.0

Reviews

1 / 10

When I was going to board, one of the staff members told me that I could not board with my passport bag because it was tree items and I would need to check a bag. This was so stupid ! The bag was small. So I had to put my things in my pockets, put the funny bag inside the other bag. Then go throw it. Then in the plane put everything back again in my funny bag.

Related info for your journey

Find useful and relevant information for your journey from Baltimore to Bismarck. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • Can I find flights from Baltimore to Bismarck for under $300 on Cheapflights?

    Yes, there are multiple flights from Baltimore to Bismarck for under $300. The cheapest flight booked recently is on Delta for just $256, but on average you can expect to pay $376.

  • Are there last-minute flights available from Baltimore to Bismarck for under $700?

    There are currently 10+ open flights from Baltimore to Bismarck within the next 7 days for less than $700.

  • What are the cheapest airlines flying from Baltimore to Bismarck round-trip?

    Cheapflights users have booked flights from Baltimore to Bismarck round-trip from $256. Another airline that can offer you cheap pricing is United Airlines. Users have found that Delta is 61% cheaper than the other options available to this destination.

  • What does BWI to BIS mean?

    This is defined as Baltimore/Washington Airport (BWI) and Bismarck Airport (BIS). Codes like Bismarck Airport are often used to just call airports uniquely.

  • Can I find deals for flights from Baltimore to Bismarck that include extra baggage allowance?

    The amount of baggage you can bring on your Baltimore to Bismarck flight depends on the airline and the type of fare you've chosen. After entering your flight details, you'll be able to view the specific baggage policies for each deal in the search results. Keep in mind that certain deals may offer additional baggage allowance.

  • Can I find deals on flights from Baltimore to Bismarck with specific airlines?

    Yes, Cheapflights allows you to browse and filter Baltimore to Bismarck flight deals by airline. After entering your origin and destination, use the available filters to view flights offered by airlines.

  • Can I find deals for flights from Baltimore to Bismarck that include hotel bookings?

    Yes. In addition to deals on Baltimore to Bismarck flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Baltimore to Bismarck?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Baltimore to Bismarck.

  • Can I find deals for business class flights from Baltimore to Bismarck?

    Yes. Cheapflights offers flight deals from Baltimore to Bismarck by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • Can I find deals for flights from Baltimore to Bismarck that allow pets onboard?

    Many airlines flying from Baltimore to Bismarck offer the option to travel with pets. After selecting a flight deal, you can find more information about the airline's pet policy on their official website or by contacting the airline directly. Please note that additional fees and restrictions may apply.

  • Can I find deals on last-minute flights from Baltimore to Bismarck?

    Yes, you can often find last-minute deals on Baltimore to Bismarck flights on Cheapflights. However, these deals can vary and may not always be available. We recommend checking back frequently or signing up for price alerts for the most up-to-date deals.

  • How recently were the Baltimore to Bismarck flight deals updated?

    The Baltimore to Bismarck flight deals you see on this page were last updated on 5/29.

  • What is the cheapest month to book a flight from Baltimore to Bismarck?

    Currently, February is the cheapest month in which you can book a flight from Baltimore to Bismarck (average of $340). Flying from Baltimore to Bismarck in July is currently the most expensive (average of $577). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Baltimore to Bismarck
See prices for flight routes from nearby airports that may be better suited for you.

Dulles Intl to Fargo flights
Reagan-National to Fargo flights
Baltimore to Fargo flights
Philadelphia to Fargo flights
Dulles Intl to Minot flights
Baltimore to Minot flights
Dulles Intl to Bismarck flights
Reagan-National to Bismarck flights
Philadelphia to Bismarck flights
Philadelphia to Grand Forks flights
Philadelphia to Minot flights
Reagan-National to Minot flights
Reagan-National to Grand Forks flights
Dulles Intl to Grand Forks flights
Baltimore to Grand Forks flights

Top 2 airlines flying from Baltimore to Bismarck

Discover the top 2 airlines that operate flights from Baltimore to Bismarck. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,784,634 searches. Data last updated mayo 30, 2024.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$286Average$599FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
American AirlinesCheapest$374Average$484FlexibilityNo cancel feeOn-time71%
Search American Airlines flights
Austin to San Francisco flights
Dallas to Phoenix flights
Baltimore to Fort Lauderdale flights
USA to Türkiye flights
Newark Airport to Los Angeles flights
USA to Sydney flights
Orlando to Las Vegas flights
New York to Washington, D.C. flights
Dallas to Denver flights
Seattle to Honolulu flights
Denver to Dallas flights
Baltimore to Benin flights

Search flights from Baltimore to Bismarck by cabin class

Find flights from Baltimore to Bismarck, based on your preferred cabin class, be it economy, premium economy, business, or first class.
First Class
Business Class
Prem Econ Class
Economy Class

Book a flight to one of these trending destinations

User searches for flights to these destinations increased 20% or more in the past 90 days compared to other destinations
Flights to Laayoune Hassan I
Flights to Virac
Flights to Figari-Sud Corse
Flights to Edremit/Korfez
Flights to Rhinelander Oneida County
Flights to Girona Costa Brava
Flights to Brainerd Crow Wing County
Flights to Parikia Paros
Flights to Cortez Montezuma County
Flights to Miyakojima Hirara
Flights to Zadar
Flights to Trapani Birgi
Flights to Provincetown
Flights to Oran Es Senia
Flights to Constanţa Mihail Kogalniceanu
Flights to Vava'u Lupepau'U
Flights to Urumqi
Flights to Hakodate
Flights to Naxos
Flights to Dalaman
Flights to Hyannis Barnstable
Flights to Devils Lake
Flights to Bastia Poretta
Flights to Karpathos

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Baltimore to Bismarck?

Cheapflights helps you search for flights from Baltimore to Bismarck via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

Why should you use Cheapflights to find cheap flight tickets from Baltimore to Bismarck?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Baltimore to Bismarck.

Can Cheapflights find flights from Baltimore to Bismarck with no change fees?

Cheapflights does show flights with no change fees to all users. To see these options for flights from Baltimore to Bismarck, users can toggle the no change fees filter when performing a flight search.

Can Cheapflights notify me if prices for flights from Baltimore to Bismarck become cheaper?

Yes! Start tracking prices for Baltimore to Bismarck flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.
View all available airlines