Oegstgeest is a town and municipality in the province of South Holland in the western Netherlands. The municipality of Oegstgeest covers an area of 7.75 square kilometers (of which 0.54 square kilometers is water). Oegstgeest lies just to the north of Leiden, with which it is conjoined in a conurbation. Oegstgeest is a separate municipality, but it is effectively a suburb of Leiden. The municipality of Katwijk is to the west, the municipality of Teylingen to the north, the Kaag Lakes (Kagerplassen) to the northeast and Leiderdorp to the east.