The "cheapest" and "fastest" don't necessarily go together. The fastest would be to rent a private car, such as www.myairportsedan.com or www.airportquickconnection.com. A less expensive (and slower) way is to use a shared ride service such as www.supershuttle.com/Locations/BWIAirportShuttleBaltimore.aspx
The least expensive (and probably slowest and most complicated) is to use www.bwiairport.com/en/travel/ground-transportation.

The idea that you'd rent and drive a car (and that would be "fastest") is actually kind of crazy. Traffic in the DC area is crazy. Naturally it depends on the day of arrival, but for me the best and only option is to take the train. There's a train station at the airport, and you have a choice of Amtrak or MARC, which is likely slower (but I've never taken it so I can't say with personal experience); just realize that you do have to take a shuttle to get to the train station, so that adds to the time, and you are subject to train schedules. But you can also take a private car service for about $90. That's not a bad deal for the distance, but you're subject to traffic delays.

If you are going to sightsee and have no definite need to be somewhere at a particular time, a car service or shuttle is fine, but Doug is correct: traffic is bad, especially in the afternoons, incredibly bad, actually. So if you have an appointment, party, event, take the train.

Sorry, I was unclear on the renting a private car. Those websites are not for rental cars, they're cars for hire with a driver...........I should have used the same terminology Ackislander did!

Not only is traffic beastly, it's rather costly to park at most of the hotels.

Alright thanks! We will take the marc!

We took the MARC train; we had to wait about 15 minutes for it to arrive at BWI, and the ride into DC didn't take very long.

Lee Ann

I don't think MARC operates on weekends.