For the Oude Rijn branch in Gelderland Province, see: Oude Rijn (Gelderland).

The Oude Rijn (Old Rhine) is a branch of the Rhine delta in the Dutch provinces of Utrecht and South Holland. Its present-day length is 52 kilometres.

In Roman times, it was the main Rhine branch, forming the northern border of the Roman Empire. In medieval times, it was used for river transport and there is a towpath along large sections of the river, many of which have been upgraded to roads over time. The river silted up in the course of the Middle Ages and had lost all of its importance by the 17th century.

Description

The city of Utrecht was founded at a ford (crossing) near the fork of river Kromme Rijn into the Vecht to the north, and the Oude Rijn to the west. Of the original fork, little remains today and both Vecht and Rijn start from the city moat. For the first few kilometres of its course, the river is channelised and known as Leidse Rijn (Leiden Rhine). It becomes the Oude Rijn after the railway bridge near Harmelen (municipality Woerden). Then it flows westward through Woerden where first the river Lindschoten branches off to the south and then the Oude Rijn forms part of the city moats.

After Woerden, the river Grecht branches off to the north and the Oude Rijn continues through the towns of Nieuwerbrug, Bodegraven, and Zwammerdam. Here the river De Meije ends into the Oude Rijn. In Alphen aan den Rijn, the Aar Canal ends in the Oude Rijn at the same location where the river Gouwe branches off to the south. It flows then along Koudekerk aan den Rijn and Hazerswoude-Rijndijk (both part of the municipality of Rijnwoude).

After Zoeterwoude-Rijndijk and Leiderdorp (where the short river Does ends), the Oude Rijn flows through Leiden. Here starts the Rhine-Schie Canal (to the south) and the stream Zijl (to the north). The Nieuwe Rijn (New Rhine) is a short branch that together with the Oude Rijn are part of Leiden's moat system and both branches merge just after the city's centre.

The stream Korte Vliet discharges into the Oude Rijn and it continues through Oegstgeest and Katwijk. From here the river has been straightened into a canal (also called Uitwateringkanaal) and ends into the North Sea.

Roman era

In Roman times, the river Oude Rijn, which was much wider, formed the Roman Empire's northern border (Limes Germanicus). Many of the border-guarding castella and castra along the river evolved into cities and villages, including: Laurum (Woerden), Nigrum Pullum (Zwammerdam), Albaniana (Alphen aan den Rijn), Matilo (Leiderdorp), Praetorium Agrippinae (Valkenburg), and Lugdunum Batavorum (Katwijk).

In Valkenburg, the layout of the Roman castellum has been marked in the pavement.

Satellite close-up of the Utrecht region showing the Leidse Rijn-Oude Rijn stream (d).

Houses on the Oude Rijn near Alphen aan den Rijn

cy:Oude Rijn de:Oude Rijn et:Oude Rijn fr:Vieux Rhin fy:Alde Ryn nl:Oude Rijn (Harmelen-Noordzee) nn:Oude Rijn