The William Dennis Weeks Memorial Library is a historic library building at 128 Main Street in Lancaster, New Hampshire, United States. The single story brick building was built in 1906 and enlarged in 1998. The original block measures 60 feet (18 m) by 40 feet (12 m), and is topped by a hipped roof which is pierced by a pair of chimneys. A central projecting entry pavilion dominates the front facade's three bays, with a recessed entry topped by a transom window and a cornice in scrolled brackets. The door surround is flanked by Doric columns set in the recessed area, and outside the recess by Ionicpilasters. Above the pilasters is an entablature and triangular pediment with decorated tympanum.