Saint-Forget (French pronunciation: [sɛ̃ fɔʁʒɛ]) is a commune in the Yvelines department in the Île-de-France region in north-central France.

[3] The commune consists of three hamlets: Le Mesnil-Sevin, Haute-Beauce, and The Sablons.

It is nestled in the heart of the Regional Natural Park of the Upper Chevreuse Valley.

[5] The commune contains a small town hall that currently offers tours and/or visits.

The castle, which used to be a manor, dates back to the 17th and 18th centuries.