The city of Simi Valley, in the eponymous valley, is in the southeast corner of Ventura County, California, 30 miles from Downtown Los Angeles

The city sits next to Thousand Oaks, Moorpark, and Los Angeles. The city's 2014 population has been estimated at 126,871. The city of Simi Valley is surrounded by the Santa Susana Mountain range and the Simi Hills, west of the San Fernando Valley, and northeast of the Conejo Valley. It is largely a commuter bedroom community, feeding the cities in the Los Angeles area and the San Fernando Valley to the east, and cities in Ventura County to the west.

The Ronald Reagan Presidential Library, where the former president was buried in 2004, is in Simi Valley. Simi Valley has been ranked twice as the 18th most conservative city in the United States; once by The Bay Area Center For Voting Research and also by GovPro.com. The Reagan Library has hosted Republican primary debates, last in 2012, and the first primary debates in 2016.  A study done by the University of Vermont ranked Simi Valley as the fifth-happiest city in the United States.  According to crime statistics by the FBI in 2013, Simi Valley is the seventh-safest city in the U.S. with a population of 100,000 or more.  The U.S. Census Bureau of 2012 reported a median household income of $87,894, which is higher than the California median of $70,231 and the national average of $62,527.