The municipality is bordered by Noordwijkerhout and Lisse to the north, Haarlemmermeer and Alkemade to the east, Leiderdorp and Leiden to the south, and Oegstgeest and Katwijk to the west. It is located in an area called the "Dune and Bulb Region" (Duin- en Bollenstreek). The Kagerplassen are to the east of Sassenheim.
The ruins of Teylingen
Dutch Topographic map of Teylingen, June 2015