Yolo County is a primarily agricultural county that was one of California's original counties at the time of statehood in 1850. The name may be derived from the Native American Yo-loy meaning "a place abounding in rushes", referring to the vast wetlands that once filled the county.
Interstate 5 enters Yolo County from the east out of Sacramento before turning northwards towards Redding, Oregon and Washington. Interstate 505 enters the county from the south before joining Interstate 5 in the northern part of the county near Dunnigan.
- 1 Colusa County - Located north of Yolo County, visitors to rural Colusa County will find an abundance of rice fields and almond trees, but a limited number of amenities and attractions. Sights that may be of interest include four national wildlife refuges, as well as the Colusa County Courthouse in the town of Colusa, which was erected in 1861 and is the oldest remaining courthouse in the Sacramento Valley.
- 2 Sutter County - Yolo County's northeastern neighbor, tiny Sutter County lies between the Sacramento and Feather rivers, with nearly 90% of the county's land used for grazing and agriculture. The county is home to the eroded volcanic lava domes of the Sutter Buttes, which occupy a circular area roughly ten miles across and are sometimes referred to as the world's smallest mountain range.
- 3 Sacramento County - Bordering Yolo County to the southeast, Sacramento County stretches from the wetlands at the edge of the San Francisco Bay to the rolling hills of Gold Country. The Sacramento and American Rivers played prominent roles in the county's development, and today offer outdoor opportunities ranging from boating to fishing to birdwatching. The capital city of Sacramento is located at the rivers' confluence, and visitors will appreciate its historic districts and more than 25 museums.
- 4 Solano County - Located south of Yolo County, Solano County is far more rural than the other Bay Area counties, and includes significant portions of the California Delta, as well as parts of San Pablo Bay. Two of the county's cities served as early state capitals: Vallejo was the capital in 1852 and again in 1853, while Benicia served as the capital from February 1853 until February 1854; today Benicia Capitol State Historic Park provides the opportunity for visitors to explore the Capitol building from that era.
- 5 Napa County - Neighboring Yolo County to the southwest, America's preeminent wine-producing region attracts more than five million annual visitors to over two hundred wineries, often overcrowding the roadways on summer weekends. Travelers will find world-famous restaurants to complement the wines, and lodging that includes luxury spas, B&Bs, and upscale hotels. Those uninterested in viticulture may choose to enjoy the hot springs of Calistoga or hike/bike the many parks and trails in the area's beautiful rolling hills.
- 6 Lake County - Rural Lake County lies northwest of Yolo County and is named after Clear Lake, a body of water that is believed to be 2.5 million years old and thus the oldest lake in North America. The lake is sometimes called the "Bass Capital of the West", and its 100 miles of shoreline offer ample opportunity for fishing, boating, swimming and birdwatching. The county is also home to the Clear Lake Volcanic Field, a region that includes lava domes, cinder cones, the 4,305 foot tall volcano Mount Konocti, and the world's largest geothermal field with more than twenty geothermal power plants.