San Francisco Peninsula region of the San Francisco Bay Area lies immediately south of the City and County of San Francisco—reaching from its famous neighbor to the north into the high-tech region of Silicon Valley. For purposes of this travel guide, the Peninsula is synonymous with San Mateo County. While many of the Peninsula's residents work and play to the north or south, the Peninsula has its attractions, including some beautiful wilderness areas.

The Peninsula has two coasts—one on the San Francisco Bay, the other on the Pacific Ocean—but few major cities or ports. The Santa Cruz Mountains divide the region in half north-south, with a large wilderness area that's great for hiking and mountain biking.