1. Sierra Nevada: This is the most well-known, stretching from north to south in the eastern part of the state. It's home to Yosemite National Park, Lake Tahoe, and the highest peak in the contiguous United States, Mount Whitney.

2. Coast Ranges: These run parallel to the California coastline, extending from the Oregon border down to the Los Angeles Basin. They're less dramatic than the Sierra Nevada, but still offer beautiful scenery and hiking opportunities.

3. San Gabriel Mountains: Located just north of Los Angeles, these mountains offer stunning views and are popular for hiking, camping, and skiing. They are part of the Transverse Ranges, a series of mountain ranges that run perpendicular to the California coast.