Lake Fenton is an unincorporated community in Fenton Charter Township, Genesee County in the U.S. state of Michigan. It is also a census-designated place (CDP) for statistical purposes and has no legal status as a municipality. As of the 2000 census, the CDP had a total population of 4,876. It includes two other recognized unincorporated communities.
The Lake Fenton Community Schools district overlaps a portion of this and adjacent areas. The school district and community named after Lake Fenton, formerly Long Lake. A community was platted as "Mount Pleasant" by John Cook in 1840, with a second plat added in 1845. The name was changed to Long Lake in 1850, and a post office with that name opened on March 6, 1851. The lake was subsequently renamed Lake Fenton and the platted settlement became extinct. In 1932, the United States Board on Geographic Names decided on "Lake Fenton" as the official name of the lake.