Obernburg stands on the Main, in the bend where the river leaves the Spessart forest and turns north, and for a time in the second century it was the frontier of the Roman world. The Odenwald Limes, the earlier version of the frontier, ran along the hills to the south and reached the river near here, and a fort was built on the bank to guard the crossing. A civil settlement grew beside it, and finds from both are shown in the town's small Roman museum, which stands on the site and has a collection of tombstones, tools and pottery.
The Limes was abandoned in the middle of the third century, when pressure from the Alemanni forced the Romans back to the Rhine, and the fort fell into ruin. The Roman line is listed by UNESCO as part of the Upper Germanic-Raetian Limes, and the section along the Main is among the quieter parts. Obernburg itself is a small town with a well-kept old centre of half-timbered houses, and Elsenfeld, a neighbour, has a more industrial character.
For a rider, the Main valley and the forested hills on either side are a good combination. The Spessart, a large wooded upland, has roads with long bends, mixed beech and oak, and few cars, and the Odenwald across the river is similar. The wine villages along the Main, the Churfranken region, grow Silvaner and Spätburgunder on steep slopes, and they have terraces where you can stop for a glass of wine and a plate of ham and bread. Miltenberg, a half-timbered town with a famous old inn, is a short ride south, and Aschaffenburg, with its Pompeian-style villa, lies to the north.
Fuel stations and supermarkets are available in Obernburg and Elsenfeld, and the area has plenty of guesthouses and cafes. The Main cycle path runs along the river, and in summer the road can be busy with cyclists. Late spring and September, when the vineyards are heavy, are the best times to ride, and a stop for local wine is best taken on foot, not before the road home.