Avenal is a city in Kings County, California, United States. Avenal is located 35 miles (56 km) southwest of Hanford, at an elevation of 807 ft (246 m). It is part of the Hanford–Corcoran Metropolitan Statistical Area (MSA Code 25260), which encompasses all of Kings County. In area, it is the largest city in Kings County. The Zip Code for this community is 93204, and telephone numbers use the sequence (559) 386-XXXX. The population was 15,505 in the 2010 census, which includes inmates at the Avenal State Prison, the first prison actively solicited by a community in the state of California. Many of the remaining residents largely either work at the prison or in the agriculture industry. The prison provides approximately 1,000 jobs to residents. The California Department of Finance estimated that Avenal's population was 13,159 on January 1, 2015. As of that date, Avenal State Prison held 4,165 inmates, which was about 32% of the total population of Avenal. Inmates are counted as city residents by both the United States Census and the California Department of Finance.