California Central Valley in the context of Elk Grove, California

Fresno County (/ˈfrɛznoʊ/ ), officially the County of Fresno, is a county located in the central portion of the U.S. state of California. As of the 2020 United States census, the population was 1,008,654. The county seat is Fresno, the fifth-most populous city in California. Fresno County comprises the Fresno, CA Metropolitan Statistical Area, which is part of the Fresno–Madera, CA Combined Statistical Area. It is located in the Central Valley, south of Stockton and north of Bakersfield. Since 2010, statewide droughts in California have further strained both Fresno County's and the entire Central Valley's water security.

The Kern River is an Endangered, Wild and Scenic river in the U.S. state of California, approximately 165 miles (270 km) long. It drains an area of the southern Sierra Nevada mountains northeast of Bakersfield. Fed by snowmelt near Mount Whitney, the river passes through scenic canyons in the mountains and is a popular destination for whitewater rafting and kayaking. It is the southernmost major river system in the Sierra Nevada, and is the only major river in the Sierra that drains in a southerly direction.

The Kern River formerly emptied into the now dry Buena Vista Lake and Kern Lake via the Kern River Slough, and Kern Lake in turn emptied into Buena Vista Lake via the Connecting Slough at the southern end of the Central Valley. Buena Vista Lake, when overflowing, first backed up into Kern Lake and then upon rising higher drained into Tulare Lake via Buena Vista Slough and a changing series of sloughs of the Kern River. The lakes were part of a partially endorheic basin that sometimes overflowed into the San Joaquin River. This basin also included the Kaweah and Tule Rivers, as well as southern distributaries of the Kings River that all flowed into Tulare Lake.

Altamont Pass, formerly Livermore Pass, is a low mountain pass in the Diablo Range of Northern California between Livermore in the Livermore Valley and Tracy in the San Joaquin Valley. The name is actually applied to two distinct but nearby crossings of the range. The lower of the two, at an elevation of 741 ft (226 m), carries two railroad rights-of-way (ROWs) and Altamont Pass Road, part of the old Lincoln Highway and the original alignment of US 50 before it was bypassed in 1937. The bypass route travels over the higher summit, at 1,009 ft (308 m), and now carries Interstate 580, a major regional highway heavily congested by Central Valley suburbanization.

Of the two railroad lines through the old pass, one is still in use: the ex-Western Pacific line built in 1908 over the pass, which is sometimes known as the Altamont Corridor, now owned by Union Pacific. It carries freight trains as well as the Altamont Corridor Express, which gives its occasional name (ACE) and operates between Stockton, Livermore, Pleasanton, Fremont, and San Jose. The other and older right-of-way was the line built in 1869 with a 1,200-foot-long (370 m) summit tunnel by the original Western Pacific Railroad (1862–1870) as part of the transcontinental railroad. After 1879, when a sea level ferry crossing at the Carquinez Strait replaced the 1869 route, it remained in use for other purposes by the Southern Pacific. In 1984 it was abandoned and deeded to Alameda County by Southern Pacific Railroad in favor of trackage rights on the aforementioned ex-Western Pacific line.

State Route 4 (SR 4) is an east–west state highway in the U.S. state of California, routed from Interstate 80 in the San Francisco Bay Area to State Route 89 in the Sierra Nevada. It roughly parallels the Sacramento-San Joaquin River Delta, a popular area for boating and fishing, with a number of accesses to marinas and other attractions. After crossing the Central Valley, the highway ascends up the Sierra foothills. It passes through Ebbetts Pass and contains the Ebbetts Pass Scenic Byway, a National Scenic Byway.

The Nisenan are a group of Native Americans and an Indigenous people of California from the Yuba River and American River watersheds in Northern California and the California Central Valley.

According to a 1929 archeology and ethnology press release by University of California, Berkeley, the Nisenan people are classified as part of the larger group of Native Americans known as the Maidu, though some dispute the accuracy of this relationship, including the Nisenan themselves. According to the Nisenan website, the United States' claim that they are Maidu is a misclassification and is inaccurate. As the Nisenan put it,

Metropolitan Fresno, officially Fresno–Hanford–Corcoran, CA CSA, is a metropolitan area in the San Joaquin Valley, in the United States, consisting of Fresno and Madera counties. It is the third-largest metropolitan region in Northern California, behind the San Francisco Bay Area and Greater Sacramento. It is also the 49th-largest CSA in the U.S. as of 2010 census.

Metropolitan Fresno is anchored by Fresno, the fifth-largest city in California and the 34th-largest in the United States. The metropolitan area is located in the Central Valley, which is one of the world's most productive agricultural regions. It has a large agricultural economy despite being increasingly urbanized. In more recent years, statewide droughts in California have further strained both the Fresno metropolitan area's and the entire Central Valley's water security.

Butte County (/ˈbjuːt/ ) is a county located in the northern central part of the U.S. state of California. In the 2020 census, its population was 211,632. The county seat is Oroville.

Butte County comprises the Chico, California, metropolitan statistical area. It is in the California Central Valley, north of the state capital of Sacramento.