In 1855, the County of Merced parted from Mariposa County and was organized with the county seat in Snelling. Over the past 150 years, Merced County grew and was incorporated in 1889. The economy has diversified over the years and in addition to agriculture, industries have entered the area including printing, fiberglass boat building, warehousing and distribution, and packaging industries.

The county's three-story courthouse, built in 1875, is one of the oldest historical buildings in California. On the National Register of Historic Places, the architectural style of the building is Italianate, designed by State Capital Architect, Albert A. Bennett. The museum houses 8500 square feet of exhibits, both permanent and rotating, which depict the history of Merced County as well as the settlers of the Great Central Valley.