Colony's Block is a historic commercial building at 4-7 Central Square in the heart of Keene, New Hampshire. The five-story brick building was built in 1870 to a design by Worcester, Massachusetts, architects E. Boyden & Son, and is the city's most prominent example of Second Empire architecture. In addition to being a long-standing commercial center, the building housed the city library from 1870 to 1877. The building was listed on the National Register of Historic Places in 1983.