Northern California is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's 58 counties. Northern California in its largest definition is determined by dividing the state into two regions, the other being Southern California. The main northern population centers include the San Francisco Bay Area, the Greater Sacramento area, the Redding, California, area south of the Cascade Range, and the Metropolitan Fresno area. Northern California also contains redwood forests, along with most of the Sierra Nevada, including Yosemite Valley and part of Lake Tahoe, Mount Shasta, and most of the Central Valley, one of the world's most productive agricultural regions. Northern California is also home to Silicon Valley, the global headquarters for some of the most powerful tech and Internet-related companies in the world, including Meta, Apple, Google, and Nvidia.