Forest is a community in Lambton Shores, Ontario, Canada, near Sarnia and Lake Huron in Lambton County. It has a population of 2,876 and a land area of 5.26 square kilometres (2.03 sq mi).

Lambton County is a county in Southwestern Ontario, Canada. It is bordered on the north by Lake Huron, which is drained by the St. Clair River, the county's western border and part of the Canada-United States border. To the south is Lake Saint Clair and Chatham-Kent. Lambton County's northeastern border follows the Ausable River and Parkhill Creek north until it reaches Lake Huron at the beach community of Grand Bend. The county seat is in the Town of Plympton-Wyoming.