Leiden, or Leyden, Netherlands, a city in Zuid (South) Holland province. It is on the Oude Rijn (Old Rhine) River near the North Sea, about 20 miles (32 km) southwest of Amsterdam. Leiden is an old, picturesque city with numerous canals. Food processing, printing, and other light manufacturing is done in the city. Nearby many tulips are grown for their bulbs.

Leiden is foremost an educational and a cultural center. The State University at Leiden, founded 1575, is the oldest and probably the most prestigious school in the nation. Cultural institutions include four national museums, chief of which is the National Museum of Antiquities.

Leiden grew around a castle and probably dates from the 11th century. During the 14th and 15 th centuries the city prospered as a textile center. A long Spanish siege (1573-74) was withstood during the Dutch war of independence; William the Silent rewarded the city by founding the university. Some of the Pilgrims lived in the city for several years before sailing to America in 1620.

Population: 118,423.