Archeologists believe Indians used Cumberland as a hunting and fishing ground as far back as 4,000 years ago. When the Spanish arrived in 1566, they named the island San Pedro and constructed a garrison and mission at the southern end named San Pedro de Mocama, which remained in operation from 1587 to 1660. Another Spanish mission on Cumberland was Puturiba, which operated from 1595-1597. An additional mission was relocated from the North Newport River to the northern end of Cumberland from 1670-1684 named San Phelipe.

The Indians they met called the island Missoe, their word for sassafras. This name didn't last long after English Gen. James Oglethorpe arrived at the Georgia coast. Turning the custom upside down, the island was named by an Indian for an Englishman. Toonahowi, the young nephew of Chief Tomochichi who visited England with Oglethorpe, suggested the island be named for William Augustus, the 13-year old Duke of Cumberland. An additional honor was a fort erected at the southern point of the island called Fort William, of which no trace remains today. Here Oglethorpe also established a hunting lodge he called Dungeness. At the northern end of the island, Oglethorpe built Fort St. Andrews, and for a decade a small village named Berrimacke existed near the fort. The forts were built to defend English settlements to the north from the Spanish in Florida. After defeating the Spanish in Battle of Bloody Marsh in 1742, the need for the forts evaporated, and the forts were abandoned and the village disappeared. The sea claimed Fort William, and most signs of Fort St. Andrews have been obliterated by time. In the 1760s, the island was divided into royal grants but saw little activity. When naturalist William Bartram visited the island in 1774, the island was mostly uninhabited.

Development of the island started in earnest after the American Revolution. Plantation owners cut and sold live oak and pine timber; grew corn, cotton, rice, and indigo on the rich soils; and raised cattle, hogs, and horses that ranged freely across the island. Perhaps the largest and most productive plantation in the region was Stafford Plantation, an 8,000-acre tract that remains in private hands today.

One of the most famous estates on the Georgia coast was Dungeness, owned by Revolutionary War hero Gen. Nathaniel Greene, who commanded the Southern Department of the war. While he owned Mulberry Grove Plantation near Savannah, he also planned to build a huge mansion on Cumberland Island near the site of Oglethorpe's Dungeness hunting lodge. He died in 1786 before he was able to complete his plans. His wife, Catherine, remarried 10 years later to Phineas Miller, and they followed through on Greene's designs, building a huge, four-story tabby mansion on top of an Indian shell mound. The mansion, with 6-foot thick walls at the base, featured four chimneys and 16 fireplaces, and was surround by 12 acres of gardens. Dungeness was the scene of many special social galas where statesmen and military leaders enjoyed the Millers' hospitality. When the island was briefly occupied during the War of 1812, the British used Dungeness as their headquarters.

In 1818, Gen. "Lighthorse" Harry Lee, Revolutionary War hero and old friend of Nathaniel Greene, came ashore at Cumberland Island. He was in failing health and was returning from the West Indies when he asked to be taken to his old friend's estate of Dungeness. After a month of illness, he died on March 25 and was buried on the island. His son, Confederate Gen. Robert E. Lee, had a tombstone placed over the grave and visited his father's final resting place several times. In 1913, Harry Lee was moved to Lexington, Virginia, to lie beside his famous son, but the gravestone was left on Cumberland Island.

From 1820 to 1838, a lighthouse operated on the southern end of Cumberland. The year a new one was established on Little Cumberland, the lighthouse on Big Cumberland was moved to Amelia Island, where it stands today.

The plantation economy was dealt a deathblow with the Civil War, and Dungeness deteriorated and the family moved away. Slaves were rounded up by the Union Army and moved to Amelia Island, but some returned to Halfmoon Bluff on the northern end in an area known as The Settlement. Freed slaves may have been the cause of the fire of 1866 that destroyed the historic mansion, and another legend tells the story of Cumberland plantation owner Robert Stafford burning the quarters of his former slaves after they refused to work for him after gaining their freedom.

The island remained abandoned until the 1880s, when Pittsburgh millionaire Thomas Carnegie, brother of Andrew, acquired the Dungeness property for use as a winter retreat. On the foundations of the Greene-Miller-Shaw Dungeness, the Carnegies built an even grander mansion in 1884. The third Dungeness, at its peak, was a 59-room turreted Scottish castle, with a pool house, squash court, and golf course, and 40 other buildings that accommodated a staff of 200. Thomas died around the time the mansion was finished, but his widow, Lucy, and their nine children continued to develop Cumberland. Lucy purchased 90 percent of the island and she and her heirs built Cumberland's most famous buildings, including Greyfield, Stafford, and Plum Orchard. Dungeness remained occupied off and on until 1959, when it tragically burned. Greyfield is a private inn and Plum Orchard, an 1898 Georgian-revival mansion, is administered by the National Park Service.

As the island passed down to successive generations of Carnegies, the heirs were confronted with what to do with their isolated property. In 1955, the National Park Service identified Cumberland Island and Cape Cod as the two most significant natural areas on the Atlantic and Gulf coasts. This increased awareness of the island, but little action was taken. In 1969, Hilton Head developer Charles Fraser, who wanted to create a similar development on Cumberland Island, purchased one-fifth of the island. When he started to bulldoze a 5,000-foot airport runway on the northern end, alarms were set off in the environmental community, which knew it was now or never to save the island. The Georgia Conservancy played a historic role in helping to push through a bill introduced by Congressmen Bill Stuckey and Bo Ginn that established Cumberland Island as a national seashore, signed by President Nixon in 1972. Most of the Carnegie heirs decided the island should remain a wilderness and worked toward that goal by selling to the federal government. The Mellon Foundation donated $7.5 million to buy up property on the island, including Fraser's tract, which then was deeded to the federal government, and most of the island became part of the park system.

A new burst of publicity occurred for Cumberland Island when John F. Kennedy Jr. married Carolyn Bessette at the First African Baptist Church on the northern end of the island in September 1996. Maintained by the National Park Service, this simple one-room frame structure, with 11 handmade pews, and three windows on each side, was built in 1937 to replace a cruder 1893 structure. The wedding party stayed at the Greyfield Inn, which was built in 1900.

Information taken from Sherpa Guides