EGLIN AIR FORCE BASE, Fla. (AP) _ The Reagan administration probably would find the isolation it is seeking for Contra training at this sprawling base in the Florida Panhandle.

Eglin, Puerto Rico and Fort Benning, Ga., all have been suggested by administration officials as possible training sites for the Nicaraguan rebels.

The military reservation at Eglin covers 724 square miles, two-thirds the size of Rhode Island.

''It's one of the few places ... where you can lose a battalion of foot soldiers and let them do their thing,'' said Lt. Col. Richard Hartman, chief of Eglin's Environmental Protection Division, during an interview last February.

Eglin officials declined comment Tuesday on the Contra proposal, saying they have been ordered to refer all questions to the Air Force Systems Command in Washington, D.C.

The base's size and isolation have made its forests, swamps, beaches and test ranges favored spots for secretive military operations from Col. Jimmy Doolittle's Tokyo raiders of World War II to cruise missile testing.

Raids designed to free captured Americans from a North Vietnamese prison camp and hostages from Iran were practiced at Eglin. Both missions failed.

Last fall, 12,000 Army, Navy, Air Force, Marine and Coast Guard personnel invaded Eglin for an excerise dubbed Bold Eagle.

The Contras wouldn't be the first Central American military unit to train here during recent tensions involving that part of the world. Two aircrews for El Salvador's first C-47 gunship were trained at Duke Field, one of several auxiliary fields that dot the reservation.

Eglin's main function is to develop and test all non-nuclear weapons used by the Air Force, but it also is home to a crack F-15 fighter wing, Army Ranger camp and other units.

Adjacent to Eglin is Hurlburt Field, home of the 1st Special Operations Wing. It was involved in the ill-fated attempted to free the hostages from Iran in 1980, losing five airmen, and the invasion of Grenada in 1983. Hurlburt also has trained foreign special forces fliers, including the Salvadorans.

During the Vietnam War, a mock Vietnamese village, complete with captured weapons and sampans, was constructed at Eglin for weapons testing and training.

Eglin also was used to test equipment for spraying the controversial herbicide Agent Orange in Vietnam. An aircraft loading area and test range contaminated by the chemical remain off-limits.

Construction crews used a million board-feet of lumber to build a mock-up of the Son Tay prison camp in North Vietnam to train troops and aircrews for the 1970 attempt to rescue prisoners from that facility. The raiders briefly captured Son Tay only to discover the prisoners had been moved.

A similar mock-up of two blocks of Japanese buildings, known as ''Little Tokyo,'' was built on the reservation during World War II to test fire bombs.

Also during World War II, Col. Paul Tibbets, pilot of the B-29 that dropped the first atomic bomb on Hiroshima, practiced for that mission over Eglin's test ranges in the Gulf.

The Doolittle raid, launched from the aircraft carrier Hornet, remains the most famous operation practiced at Eglin, although he and his B-25 crews spent only two weeks here in 1942.

A naval aviator from the nearby Pensacola Naval Air Station came to Eglin to teach Doolittle's Army pilots how to get their bombers airborne within the length of a carrier's deck.