Located at the junction of Highway 101 and State Hwy 6, the museum is housed in the second county courthouse, built in 1905. It is on the same site as the original building, which burned in 1903.
When the present courthouse was built in 1932, the older building was turned into a museum through the efforts of local volunteers who formed the Tillamook County Pioneer Association. There are now over 35,000 artifacts.
The Tillamook County Pioneer Museum Library contains well over 3,000 volumes, with 20% of the collection devoted to genealogy.