The park contains the Fort Borst Blockhouse. The block house was built in 1855 for defense against Native American uprisings. Flood waters converging on its original site, at the confluence of the Skookumchuck and Chehalis Rivers, necessitated removal of the structure to the present location near the south end of Borst park. The old blockhouse, still in good condition, is the park’s chief attraction. The foundation walls of hewn and dovetailed fir logs rise ten feet to support the overhanging upper fortification. The floor in the extension of this second story is perforated with holes for firing down upon attackers. Floors and doors are of cedar puncheons, heavy enough to resist an arrow or check a musket ball. The usual loopholes for rifles were cut around the sides.