The Frost Free Library was constructed privately by Rufus S. Frost (1826-1894) as a gift to the Town of Marlborough, New Hampshire. A native of Marlborough where his family had lived for several generations, Frost and his family moved to the Boston in 1833. As a young adult, Frost worked in a dry goods store, eventually becoming a wealthy merchant and woolen manufacturer. Frost held public office as Mayor of Chelsea, Massachusetts (1867-68), Massachusetts State Senator (1871-72), and as a Representative to the United States Congress (1875-76). Having maintained active familial connections to Marlborough throughout his life, Frost negotiated with the town to create and donate a library that would not financially burden Marlborough.
Local histories report that Frost purchased a piece of land in 1865 and built the library in the summer and fall of 1866, reportedly supervising construction himself. There are no known plans or financial accounts of the building’s construction; however the use of granite structural elements for walls and flooring, as well as a vaulted ceiling that appears to have been plastered with mortar suggest that fire-resistance was an important consideration in the building’s design. In 1866, Frost donated the library to the town together with a fund to support its operation.