Lake Fenwick is located in King County, Washington, United States, mostly within the city of Kent.

[3] Lake Fenwick also suffers from a large population of invasive Egeria densa, or Brazilian elodea.

[1] This plant, classified as a noxious weed in the state of Washington, forms dense mats that harm ecosystems, reduce water quality, and stifle recreational activities.

The lake is stocked with rainbow trout annually by the Washington State Department of Fish and Wildlife.

Other species naturally present in the lake include black crappie, brown bullhead, largemouth bass, pumpkinseed sunfish, and yellow perch.