Leiden is a city and municipality located in the province of South Holland, Netherlands. It is situated on the Oude Rijn river, positioned approximately 20 km north of The Hague and 40 km south of Amsterdam. To its northeast lies the recreational area known as the Kaag Lakes (Kagerplassen).
The municipality of Leiden has a population of 127,046. However, it forms a densely connected agglomeration with the suburbs of Oegstgeest, Leiderdorp, Voorschoten, and Zoeterwoude, which together house 215,602 inhabitants. When including Katwijk, the total population of the Leiden urban agglomeration reaches 282,207. The broader Leiden urban area, which further includes Teylingen, Noordwijk, and Noordwijkerhout, has a total population of 365,913.