The Oder-Neisse line is Germany’s border with Poland, following the rivers Oder and Neisse on the frontier set in 1945.
There’s a cycle route on each side of the Oder: this is the German one, with the Zielona Odra on the Polish side. It’s very flat and very rural: Frankfurt an der Oder (not to be confused with the one on the Main) and Eisenhüttenstadt are the only places of any size along the Oder.
Don’t expect the dramatic scenery of the Saar-Mosel-Main route, or even the Rhine. The Oder is a river of wide floodplains, and in the lower river, this means a remarkable variety of wildlife: beavers, cranes, black storks, white-tailed eagles. But as you proceed upstream, you’ll often find that the floodbanks prevent views of the river itself.
At Ratzdorf, the frontier leaves the wide Oder for the much smaller Neisse. The cycleway is still good quality and mostly paved, and although the surrounding landscape remains flat and uneventful, you’ll see much more of the water than you did before.
The hills finally close in after Görlitz, and the tree-lined route from here, through Zittau, to the Czech border is delightful. The route continues towards the source of the Neisse as Czech route 3038, inevitably hillier and mostly on quiet lanes.