Its county seat is Green Cove Springs, Florida. Clay County is part of the Greater Jacksonville Metropolitan area.
Clay County was once a popular destination for tourists visiting from the northern states. The therapeutic, warm springs and mild climate were major draws for visitors. Steamboats brought them to various hotels in Green Cove Springs - the St. Elmo, Clarendon and the Oakland. President Grover Cleveland was the most prominent of such tourists; he had spring water shipped to the White House. Clay County's popularity among tourists peaked during the last three decades of the 19th century. It was later eclipsed by Henry Flagler's extension of the Florida East Coast Railway to points south such as Palm Beach and Miami.
The military has also played an important role in Clay County history. In 1939, Camp Blanding opened on Kingsley Lake in central Clay County. The Florida National Guard developed this 28,000 acre (113 km²) complex. During World War II, it trained over 90,000 troops and became the fourth largest 'city' in the state. In Green Cove Springs, Lee Field was a flight training center. After World War II, Lee Field became a base for the mothball fleet. Although Lee Field closed in the early 1960s, Camp Blanding continues to operate today. Clay County is also a popular choice of residence for military personnel who are stationed on bases in nearby Duval County (NAS Jacksonville, NS Mayport).
There were 50,243 households out of which 39.60% had children under the age of 18 living with them, 63.80% were married couples living together, 10.70% had a female householder with no husband present, and 21.60% were non-families. 16.90% of all households were made up of individuals and 5.50% had someone living alone who was 65 years of age or older. The average household size was 2.77 and the average family size was 3.11.
In the county the population was spread out with 28.00% under the age of 18, 7.90% from 18 to 24, 30.30% from 25 to 44, 24.00% from 45 to 64, and 9.80% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 97.00 males. For every 100 females age 18 and over, there were 94.20 males.
The median income for a household in the county was $48,854, and the median income for a family was $53,814. Males had a median income of $36,683 versus $25,488 for females. The per capita income for the county was $20,868. About 5.10% of families and 6.80% of the population were below the poverty line, including 8.90% of those under age 18 and 7.40% of those age 65 or over.
According to the Florida Times-Union, in October 2004, there were 106,114 registered voters in Clay County.
Learn more about Clay County, FL with the Clay County Economic Development division
Clay County is one of the most reliably Republican counties in the state during presidential elections outside of the Panhandle, although it often supports Conservative Democrats for local and state offices.
| Year | Republican | Democratic | Other |
|---|---|---|---|
| 2004 | 76.2% | 23.3% | 0.5% |
| 2000 | 72.8% | 25.5% | 1.7% |
| 1996 | 64.5% | 28.2% | 7.4% |
| 1992 | 58.0% | 23.3% | 18.7% |
| 1988 | 76.7% | 23.0% | 0.3% |