Knollcrest is a census-designated place (CDP) in the town of New Fairfield, Fairfield County, Connecticut, United States. It is in the northeastern part of the town, on a peninsula on the western side of Candlewood Lake. It is bordered to the northeast, across Squantz Cove, by Bogus Hill. As of the 2020 census, Knollcrest had a population of 334.
Knollcrest was first listed as a CDP prior to the 2020 census. The community was established in 1936.
Knollcrest is known for its Dutch-style windmill. It was constructed in 1936 as a functional water pump. The structure is 80 feet tall and houses a 3,000 gallon copper water tank. The windmill currently serves as the main office for the community. It was commissioned by the Homelander Company and was designed by Charles A. Federer.