[1] The museum's site at PCC's Rock Creek Campus also includes a research library and is home to the original Washington County Jail built in 1853.

[2] In the 1930s, local historian Albert E. Tozier donated his collection of artifacts, books, maps, and other items to the county historical society.

[12][16] The former museum building at PCC underwent renovations in 2014–2015, and continued in use as a repository for the county archives and an historical research facility.

[21] In September 2017, the museum's board voted to leave the Hillsboro Civic Center location in downtown and move its exhibits back to PCC Rock Creek.

[22] The increase in attendance that the 2012 move to downtown Hillsboro – a higher-profile, more accessible location – had been expected to generate failed to materialize.

[22] The museum closed permanently at the Hillsboro Civic Center in September[22] and reopened at PCC Rock Creek on October 25, 2017.

[26] The PCC Rock Creek location is the Robert L. Benson Research Library with over 25,000 images, more than 1,400 maps, and over 500 books along with other historical records and newspapers.

The Rock Creek location also serves as the collection storage facility housing over 40,000 artifacts and items of historical significance to the County's history, and is open by appointment only.

[31] Other artifacts in the collections range from everyday items such as sewing machines, to a wedding dress of a local prominent family.