The story of this park is intertwined with that of Mike Kelly, Highline’s first overland pioneer, and with the many twists and turns of “his” road—Des Moines Way. Mike Kelly built the first road from South Park to the area he named Sunnydale in the 1870s. Except for Military Road, the only link between Seattle and the settlers along the Duwamish River Valley, and as far south as Kent, had been by small steamboat.
Sunnydale held some of the richest soil in King County. As more homesteaders arrived, they “traded days” to build one another’s homes. Eventually the Kelly Road became Des Moines Way, a vital commercial and commuter route between Des Moines and Seattle. The area's first school, the Kellys' log cabin, eventually became Sunnydale School—still in use today—site of Des Moines Memorial Park and Monument.