Mount Oso, Mountain summit in Stanislaus County, California, US.

Mount Oso is a summit in the Diablo Ranges located in western Stanislaus County, reaching approximately 3,350 feet. The mountain sits on private property with gates controlling access to the hiking trails that lead up the slopes.

Mount Oso, Spanish for "bear", was probably first sighted by Gabriel Moraga during his expeditions into the Central Valley. No exact date is recorded for the first ascent. The peak later carried radio stations and an unused forest fire lookout tower, and it appears in the City of Modesto's logo because of its place on the local skyline.

The mountain serves as a local landmark that residents recognize and reference in daily directions and regional identity. People view it as a defining feature of the valley landscape and point to it when describing where they live.

Visiting requires advance permission since the mountain sits on private property with restricted access points. Plan your trip ahead and contact the property owners beforehand, as conditions and access availability can change throughout the year.

The summit holds broadcasting equipment and an abandoned fire observation tower from an earlier era. This historic structure reflects how the hilltop once served as a vantage point for monitoring the surrounding landscape for wildfires.