Satellite image of the central part of the Rhine-Meuse delta showing the city of Utrecht and its surroundings, including the Kromme Rijn branch (b).

In Roman times, this northernmost branch of the Rhine delta now called Kromme Rijn ("Crooked" Rhine, for its many bends) was the main distributary of this major European river. It is along her banks that the Romans built their frontier fortifications known as Limes and it is this waterway that carries the name "Rhine" to the North Sea.

Since the Middle Ages, however, the stream lost its importance as it silted up, and eventually it was cut off from the Nederrijn-Lek main artery. The stream twists and turns through the province of Utrecht, past the towns of Bunnik and Zeist, and ends in the moat of the city of Utrecht.

Originally, the city of Utrecht was built by the Romans at a ford near the place where the Kromme Rijn forks into rivers Vecht (north) and Leidse Rijn (west); the last stretch within the city walls, however, was channelised to form the Oude Gracht canal. Rivers Leidse Rijn and Vecht now extend from the city moat.