Marburg sits on the Main-Weser Railway, which connects it directly to Frankfurt (about 75 minutes) and to Kassel to the north. Trains run regularly throughout the day. The station is about 15 minutes' walk north of the old town — a flat walk along the Lahn, with the old town rising steeply to your left.
By car, Marburg is reached via the A49 autobahn from the south or the B3 road from Frankfurt. Driving into the old town is inadvisable — parking is limited and the streets are narrow. Use the park-and-ride at the station.