Trout Brook Provincial Park is a day-use picnic park situated on the shores of Lake Ainslie in East Lake Ainslie, Cape Breton Island, located approximately 22. 5 km south of the junction of Routes 19 and 395.

It offers one of the few public access points to Lake Ainslie, part of the Margaree–Lake Ainslie Canadian Heritage River system.

Visitors can picnic beneath a mixed-wood forest before reaching a white sandy beach on the lake, which is suitable for swimming and trout fishing.

The park forms part of a protected natural corridor — alongside Trout Brook Wilderness Area and Humes River Wilderness Area — stretching from Bras d'Or Lake to Lake Ainslie across the Keppoch Plateau.