MASN can be found on Channel #640 on the DIRECTV Channel Lineup.
This channel is also available in HD (High Definition).
If you want to know what DIRECTV programming packages carry MASN, you will only be able to find it in:
Mid-Atlantic Sports Network (MASN) is a regional network that delivers local sports coverage from MLB baseball to college basketball and more. If you are a fan of the Washington Nationals or Baltimore Orioles then you will be able to catch their games as MASN televises these teams exclusively.