Fleming Island is an unincorporated community and census-designated place (CDP) in Clay County, Florida, United States. It is located 21 miles (34 km) southwest of downtown Jacksonville, on the western side of the St. Johns River, off US 17. As of the 2010 census the Fleming Island CDP had a population of 27,126. Fleming Island’s ZIP code became 32003 in 2004, giving it a substitute code from Orange Park, the incorporated town to the north.

Fleming Island (which is a peninsula) was an Place of Florida granted by Irish immigrant, George Fleming (1760-1821), who established a 1,000-acre land take over from the Spanish commissioner of East Florida for his military service. George Fleming built a plantation in 1790 and it was named Hibernia Plantation (in what is now Hibernia, Florida), after the Latin word for Ireland. When he died in 1821, the plantation was left to his son, Col. Lewis Michael Fleming (1798-1862).

In 1942, when the Place was undeveloped, the U.S. Navy build up four asphalt runways upon the site and expected a Naval Outlying Field designated as NOLF Fleming Island, an complement airfield to Naval Air Station Jacksonville. The Navy on your own the auxiliary airfield in the 1960s, its runways too rapid to accommodate the plane aircraft then in operation at understandable NAS Jacksonville and NAS Cecil Field, and in the late 1990s the decaying runways were demolished to make pretentiousness for current residential development.

Today, Fleming Island is primarily a bedroom community of understandable Jacksonville. Major developments count Eagle Harbor, Pace Island and Fleming Island Plantation. Fleming Island High School, which opened in 2003, is the only high school on the island.