Sugarloaf Ridge State Park in the Mayacamas Mountains northeast of Kenwood spans the Sonoma-Napa county line and protects the headwaters of Sonoma Creek, rugged ridges, forests, chaparral, and Bald Mountain. The area was first inhabited by the Onasáti, a Wappo people settled along Sonoma Creek about 1,500 years ago, before disease and forced relocation devastated surviving communities. Farming expanded there by the 1870s, and land bought by the state in 1920 was later used for Camp Butler and grazing before becoming a state park in 1964. Known for its trails, observatory, wildlife, and broad views, it also became a symbol of park funding struggles before volunteers reopened and continue operating it.