The Middlesex County Courthouse is a historic courthouse building in East Cambridge, Massachusetts. It was initially designed in 1814-1816 by noted architect Charles Bulfinch (1763–1844), and subsequently enlarged in 1848 by Ammi B. Young. The original courthouse was given by Andrew Craigie as part of his scheme to develop East Cambridge. Bulfinch created its plans, and it was erected 1814-1816 on Third Street between Otis and Thorndike Streets. His original stuccoed building is now known by only one surviving sketch, and forms the central core of today's building.