Forest Glen is Community Area 12 of the city's 77 official neighborhoods.

The approximate boundaries of Forest Glen east of Cicero Ave (4800 W) are Bryn Mawr Ave (5600 N) and C&NW tracks to Devon Ave (6400 N), Pulaski Rd (4000 and C&NW tracks west to Cicero. The westerly portion of Forest Glen is bounded on the south by Foster Ave (5200 N), on the north by the city limits, on the east by Cicero Ave (4800 W), and on the west by Lehigh Ave south of Devon Ave (6400 N) and Caldwell Ave north of Devon.

Forest Glen includes Sauganash and also includes Edgebrook and its five micro-neighborhoods (Middle Edgebrook, North Edgebrook, Old Edgebrook, South Edgebrook and Wildwood).

The area that's commonly referred to as Forest Glen today is the area south of Forest Glen Ave.