Alexander Gillon (August 13, 1741 – October 6, 1794) was an American merchant and seaman from Charleston, South Carolina. He represented South Carolina in the U.S. House in 1793 and 1794.

Gillon was born in 1741^[1] in Rotterdam in the Dutch Republic of Scottish parents. He pursued an education in London and stayed there for some time. He became a sea captain and in 1765 sailed to Charleston, South Carolina, in the brigantine Surprize.^[2] He returned in 1766 in the brigantine Free-Mason [sic]. While in Charleston Gillon married Mrs. Mary Cripps, a widow from Kent residing in the city. He sailed back to Britain shortly after his marriage but then returned to Charleston that same year. On February 10, 1789, he married Ann Purcell, the daughter of Reverend Henry Purcell, rector of St Michael's Church in Charleston. He was also an owner of 106 slaves.

In 1766 he settled in Charleston and established a large business. Some ten years later he became involved in politics. He was a delegate to the Second Provincial Congress of South Carolina in 1775 and 1776 and was a member of the first general assembly in 1776.

His men elected him captain of the German Fusiliers of Charleston in May 1775. Three years later South Carolina appointed him Commodore of the South Carolina Navy and sent him to France to procure vessels for the Navy.

In 1780 he chartered Indien from the Duke of Luxembourg on behalf of South Carolina and the South Carolina Navy, for a quarter-share of her prizes. Gillon renamed the frigate South Carolina.

In 1781 the South Carolina, manned by American officers and a group of European seamen and marines, sailed across the Atlantic toward Charleston. When she found that the British had already occupied that city she sailed to Cuba.

Between August and October 1781 she captured a cutter, a privateer, the brig Venus and seven other vessels.

South Carolina arrived at Havana on January 12, 1782. At Havana, after negotiations between Gillon and the Spanish, the South Carolina joined a force of 59 vessels sent to capture the British colony of New Providence in the Bahamas.^[2] On April 22 the expedition sailed and by May 5 the whole fleet had reached New Providence. On May 8 the colony surrendered. This was the third capture of New Providence during the American Revolutionary War.

South Carolina then sailed north, arriving at Philadelphia on May 28 . Here she remained nearly six months. While she was there the Duke of Luxembourg dismissed Gillon and replaced him as captain with Captain John Joyner. Shortly thereafter the British frigates HMS Diomede, HMS Quebec, and HMS Astraea captured South Carolina.

He was the founder and first president of the Charleston Chamber of Commerce.

In 1784 he was elected to the Continental Congress but did not attend. Four years later he was a delegate to the State convention that ratified the Federal Constitution in 1788. Next, he was elected as an Anti-Administration candidate to the Third Congress. He served from March 4, 1793, until his death on October 6, 1794, at his plantation. He was buried in the family burial ground at the plantation “Gillon’s Retreat,” Orangeburg District, Calhoun County, South Carolina.

• List of United States Congress members who died in office (1790–1899)