Glenn County is in the California Central Valley. As of 2010, it had a population of 28,122. The county seat is the city of Willows.

Glenn County was formed in 1891 from parts of Colusa County. It was named for Dr. Hugh J. Glenn, who was the largest wheat farmer in the state during his lifetime, and a man of great prominence in political and commercial life in California

According to the 2000 census, the county has a total area of 1,327.16 square miles (3,437.3 km²), of which 1,314.79 square miles (3,405.3 km²) (or 99.07%) is land and 12.36 square miles (32.0 km²) (or 0.93%) is water.

Glenn is a strongly Republican county in Presidential and congressional elections. The last Democrat to win a majority in the county was Lyndon Johnson in 1964.

Glenn is part of California's 2nd congressional district, which is held by Republican Wally Herger. In the State Assembly, Glenn is part of the 2nd district, which is held by Republican Jim Nielsen. In the State Senate, Glenn is part of the 4th district, which is held by Republican Doug LaMalfa.

California (pronounced ⁱ/kælɨˈfɔrnjə/) is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third most extensive (after Alaska and Texas). It is home to the nation's second- and sixth-largest census statistical areas (Los Angeles Metropolitan Area and San Francisco Bay Area), and eight of the nation's fifty most populated cities (Los Angeles, San Diego, San Jose, San Francisco, Fresno, Sacramento, Long Beach and Oakland). The capital city is Sacramento.

California's diverse geography ranges from the Pacific Coast in the west, to the Sierra Nevada mountains in the east – from the Redwood–Douglas-fir forests of the northwest, to the Mojave Desert areas in the southeast. The center of the state is dominated by Central Valley, a major agricultural area. California contains both the highest and lowest points in the contiguous United States (Mount Whitney and Death Valley), and has the third-longest coastline of all states (after Alaska and Florida). Earthquakes are a common occurrence due to the state's location along the Pacific Ring of Fire: about 37,000 are recorded annually.