Lac Gregory is a body of fresh water crossed from north to south by the Tourilli River, located in the Laurentides Wildlife Reserve, in the unorganized territory of Lac-Croche, in the La Jacques-Cartier Regional County Municipality, administrative region of Capitale-Nationale, in province from Quebec, to Canada.

The watershed of Gregory Lake is served by a few secondary forest roads for the needs of forestry and recreational tourism activities.

[2] The surface of Lake Gregory is generally frozen from the beginning of December to the end of March; safe circulation on the ice is generally done from the end of December to the beginning of March.

This lake between the mountains is akin to the following three bays: The mouth of Gregory Lake is located 2.7 kilometres (1.7 mi) northeast of Tourilli Lake, 10.4 kilometres (6.5 mi) west of the course of Jacques-Cartier River and 32.5 kilometres (20.2 mi) north of the confluence of the Tourilli River and the Sainte-Anne River.

[2] The toponym "Lac Gregory" was formalized on December 5, 1968, by the Commission de toponymie du Québec.