Exploration of the area in the late 1700s and early 1800s was limited to a few hardy individuals like Captain George Vancouver who explored and named Hood Canal, and the Wilkes expedition which explored the Puget Sound waters.

Thomas Webb and Franklin Purdy became the first known settlers to move into the area. As a result of their 1851 settlement of the Skokomish Valley, the doors of the area seemed to open up. Mason County was created and organized a few years later when the Washington Territorial Legislature divided Thurston County. For the first ten years of existence, the county was called Sahewamish County. In 1864, the name was changed to Mason in honor of honorable Charles H. Mason, the first Washington secretary.

As the forest industry began to develop, so did the logging camps and sawmills that harvested and cut the rough timber. By the end of the 1850s there were several mills operating throughout Mason County.

By 1887 three railroads were operating and moving timber within the borders of Mason County.

Farming, fishing and the oyster industry were also beginning in other areas of the county at that time. The first shipment of oysters from Oyster Bay left Kamilche in 1878.

By 1888, Shelton had grown into a fair-sized city with a newspaper, schools, hotels, a funeral home and railroads. Many other communities like Union, Allyn and Matlock began to thrive at the same time and continue to be active.