The library contains over 6500 volumes relating to various subjects such as archaeology, decorative arts, material culture, cooking and horticulture. Also included are volumes pertaining to local and regional histories and museum studies.
Books circulate to museum staff and members only.
The archives contain large manuscript and photograph collections which document the Portsmouth area and its neighborhoods. The manuscript collections are closely tied to the houses and families which make up the museum. Some notable collections include the papers of Ichabod and Sarah Parker Rice Goodwin , Governor John Langdon and the Chase family. Thayer Cumings Library and Archives is primarily a research facility for museum staff. However, the public is welcome to use the library on Tuesdays from 10 am to 1 pm and Thursdays from 1 - 4 pm.