Materials not maintained in the Deats Library and two basement archival vaults beneath it are stored in the Society’s two-story, all-concrete, state-of-the-art, environmentally-controlled archives building at 67 River Road in Raritan Township, designed to serve archival needs for the next 50 years. Not planned for public use, the building was opened for tours upon its completion in 2009 after ten years of planning and fundraising. Quilt turnings have been held there and more tours will be scheduled in the future.

A sampling of the Society’s collection includes Lenape Indian artifacts; genealogies of 1,200+ Hunterdon families; family bibles; wills; deeds; census, church, civic group and business records; original source historical manuscripts; photographs; maps; quilts; costumes and other textiles; and 1,181 microfilm rolls of County newspapers since 1825 — and more items are continually being added through the generosity of Hunterdon families.