Courthouse Square Historic District, also known as Courthouse Square District, is a national historic district in Greencastle, Indiana, United States. Centered on the Putnam County Courthouse, the district includes seventy-six different contributing properties. Since the first years after Greencastle was platted in the early nineteenth century, the land included in the district has been the center of commerce and government for the area. The current courthouse, built in 1905, is the fourth building to occupy the site.In 1984, the historic district was added to the National Register of Historic Places.