Zijl

thumb|250x250px|Recreational boating on the Zijl; in the background, the Boterhuispolder.

The Zijl (formerly known as Zyl) is a short river in the Dutch province of South Holland that connects the Old Rhine (Oude Rijn) with the Kagerplassen. The Zijl flows in a south–north direction and is only 4.56 kilometers long, running from the Spanjaardsbrug in the city of Leiden to the Kager plas Zweiland. There are two islands in the Zijl: Zijleiland and Boterhuiseiland. The northern section was previously referred to as the Rechte Zijl, while the southern part was known as the Kromme Zijl.