The Museum is a private non-profit educational organization that is the home of Clinton's landmark Red Mill. With over 40,000 artifacts, the Museum chronicles more than 180 years of Hunterdon County history. The largest of the Museum's artifacts is the showpiece Red Mill. Built in 1810, the mill was used for processing wool, grist, plaster, graphite and talc, generating electricity, pumping water and even peach basket production. The "monitor", a roof line extension which was added in 1908, to accommodate new machinery, gives the mill its distinctive appearance. Today, the four floors of the Mill showcase artifacts of Hunterdon County's rural, agricultural, and commercial heritage.

On the Museum grounds is an 1860, one-room School House and a reproduction 18th century Log Cabin, complete with Herb Garden and stone Spring House. Nearby Carriage Sheds display a large variety of wagons, carriages, sleds, and 19th century agricultural equipment.

A significant portion of the Museum's nine acres is the home of the Mulligan Quarry. The Quarry was operated in 1848 by three Irish immigrant brothers and remained in Mulligan hands until the early 1960s. The limestone quarry is the site of many of the Museum's special events and education programs. Rolling terrain, situated above the river banks, provides relaxing lawn seating against the dramatic backdrop of 150 foot high limestone cliffs. A number of structures, dating from the 1850s to circa 1912, stand and function as interpretive and exhibit areas. These include the Quarry Office, Tenant House, (part of which interprets a turn of the century general store), a functioning Blacksmith Shop, Dynamite Shed, Worker's Shack, and Rock Screening House.