The Danube here is already a serious river, and about two thousand years ago it was the edge of the Roman Empire. Abusina, the Roman fort at Eining, stood on the south bank, where a small tributary joins, and its soldiers watched the Germanic lands across the water. The site lies in a bend a few kilometres from Neustadt an der Donau, and what remains are the foundations of a fort that was rebuilt several times, and of a civilian settlement, with a bath house, whose walls you can see outlined in the grass. The fort ended its life in the fifth century, in the unsettled times when Rome let go of the frontier.
It is a quiet site, partly covered by a small village and a church, with a reconstructed section of wall and an information trail. What strikes you is the openness, with fields on all sides and the river nearby, and the sense of a long and lonely posting. The Raetian frontier is part of the UNESCO listing for the Roman limes, and Abusina is one of its better-known forts in Bavaria.
Just a few kilometres upstream the Danube cuts a narrow gorge through the Jurassic limestone, the Donaudurchbruch near Kelheim, with white cliffs on both banks. Weltenburg Abbey, one of the oldest monasteries in Bavaria, sits at the entrance and brews a well-known dark beer, with a beer garden by the river. Boats run through the gorge from Kelheim, and the road along the river is a lovely ride, with curves between the cliffs and the trees.
Neustadt an der Donau, with almost 13,000 people, and Abensberg, nearby, have fuel, supermarkets and cafés. Abensberg is the heart of the Hallertau, the world's largest hop-growing region, and in late summer you ride past fields of tall hop poles, covered in bright green vines. A tower by Friedensreich Hundertwasser at the Kuchlbauer brewery is a surprising sight in the countryside. Spring and early autumn are the best seasons, and weekends in summer can be busy with cyclists on the Danube path. Stop for a beer and a pretzel and look at the water.