The Alewife Brook Reservation is a state park and recreation area in Cambridge, Massachusetts. It is described as an ?urban wild, which is basically a natural ecosystem that is preserved in the midst of a highly developed locale.

Covering 120 acres, the Alewife Brook Reservation is one of metropolitan Boston?s largest urban wilds. It is composed of varying natural habitats, mostly wetlands that include the Little River, as well as a wooded upland and meadows. The site is home to many migratory and indigenous birds like osprey, woodcock, and great blue heron. It also contains two ponds (Little and Blair) which are spawning grounds for anadromous herring.

Visitors of the Alewife Brook Reservation can enjoy hiking, birding, and picnicking at the site.