The Middlesex County Hospital was operated by Middlesex County from the 1930s until 2001.

Its property straddles the towns of Waltham and Lexington, Massachusetts.

Originally a tuberculosis hospital, it eventually became the county hospital for Middlesex until its closure.

[1] The property was sold and redeveloped into a condominium community.

It is located near the old Metropolitan State Hospital, which was closed in 1992 and has also been redeveloped into housing.