The Kromme Rijn (Dutch pronunciation: [ˈkrɔmə ˈrɛin]; "Crooked Rhine", for its many bends) is a river in the central Netherlands.
In Roman times, this northernmost branch of the Rhine delta was the main distributary of this major European river. Along its banks the Romans built their frontier castella part of the Limes Germanicus.
The Lek (Dutch pronunciation: [lɛk]) is a river in the western Netherlands of some 60 km (37 mi) in length. It is the continuation of the Nederrijn after the Kromme Rijn branches off at the town of Wijk bij Duurstede. The main westbound waterway is hereafter called the Lek River. The Nederrijn is, itself, a distributary branch of the river Rhine.
Portions of the river form the boundary between the provinces of Utrecht and Gelderland, and between Utrecht and South Holland.
The Nederrijn (Dutch pronunciation: [ˈneːdəˌrɛin]; "Lower Rhine"; distinct from the Lower Rhine or Niederrhein further upstream) is the Dutch part of the Rhine from the confluence at the town of Angeren of the cut-off Rhine bend of Oude Rijn (Gelderland) and the Pannerdens Kanaal (which was dug to form the new connection between the Waal and Nederrijn branches). The city of Arnhem lies on the right (north) bank of the Nederrijn, just past the point where the IJssel branches off. The Nederrijn flows on to the city of Wijk bij Duurstede, from where it continues as the Lek. The once-important but now small Kromme Rijn branch (in Roman times part of the Limes Germanicus and border river of the Roman Empire) carries the name "Rhine" towards the city of Utrecht.
From the city of Utrecht, the Kromme Rijn forks into the Vecht to the north, and into the Oude Rijn (Utrecht and South Holland) to the west. The first part is channelised and known as the Leidse Rijn (Leiden Rhine). After the railway bridge near Harmelen (municipality Woerden) it is known as the Oude Rijn, flowing westward to the North Sea.
Dorestad (Dorestat, Duristat) was an early medieval emporium, located in the present-day province of Utrecht in the Netherlands, close to the modern-day town of Wijk bij Duurstede. It flourished during the 8th to early 9th centuries, as an important port on the northeastern shipping routes due to its proximity to the fork in the Rhine, with access to Germany via the Nederrijn (the northernmost branch of the Rhine), to the southern Netherlands, northern France, and England (via the Lek), and to the northern Netherlands, northern Germany, and Scandinavia (via the Kromme Rijn).