Ingleside is an unincorporated community in Lake County, Illinois, United States. Ingleside is between Fox Lake, Round Lake Heights and Lake Villa.
Ingleside is on Squaw Creek (also called Indian River) between Long Lake, Duck Lake, and Fox Lake.
Ingleside lies below the Long Lake Dam and above Fox Lake. Duck Lake and most of the Long Lake area are part of Ingleside. Ingleside also goes northeast to Lake Villa.
Notable locations include the Old Grant Township Hall (home of the Grant Township Museum), the Long Lake Dam, the Fox Lake bike trail, Dry Dock Laundromat, and Dog n Suds, a 1950s-style drive-up complete with intercoms for ordering and carhops to bring customers their food. They have a weekly classic car night and are open Tuesday–Sunday seasonally.
The primary elementary school district is Gavin School District 37.
In the 1960s, mammoth bones were found there.