The distance from Ann Arbor to Washington is approximately 800 kilometers. The most practical way to travel is to drive to Detroit Metropolitan Airport (DTW) and fly to Washington (DCA or IAD). Driving is possible but takes over 10 hours. Washington is the capital of the United States and is famous for its monuments and museums.
Total Distance: 800 km driving, 700 km air distance.
Reagan National (DCA) is the most convenient airport for downtown Washington.
April to June or September to October for mild weather.