John Edgar (ca. 1750–1832) was an Illinois pioneer and politician. He was born in Ireland. In 1776, he was the commander of a British ship in the Great Lakes. He resigned from the British Navy rather than fight against the Americans.
Edgar came to Kaskaskia in 1784 after being a prisoner of the British during the Revolution and later serving as a ship's captain for the U.S. Navy. He became a powerful politician and the largest owner of land in the region, William Clark, of the Lewis and Clark expedition, had met him in 1797 after traveling overland to Kaskaskia from Kentucky.
Edgar settled at Fort Kaskaskia in 1784. He became a merchant, and built a flour mill. He shipped large quantities of flour from Illinois to New Orleans.
Edgar was an Illinois delegate to the Legislature of the Northwest Territory. He also served as Justice of the Peace and Judge in Kaskaskia.
In his time, Edgar was believed to have been the wealthiest man in Illinois. He held many large land claims around the State. Edgar County, Illinois was named in his honor.
John Edgar was an officer in the British Navy during the Revolutionary War. He married an American wife who was an able person and much devoted to the cause of the colonists. This attitude on the part of his wife must have greatly influenced Edgar, for we shortly find him helping his wife in her efforts to further the interest of the rebellious colonists. When knowledge of these actions came to the British authorities, John very prudently fled, reaching Kaskaskia in 1784. His rather extensive property, excepting about $12,000 which his shrewd and capable wife managed to secure, was confiscated by the British. With this money, she joined him in 1786. Edgar at once began various ventures and became very wealthy. Among other activities he was a land speculator on a vast scale. John’s taste for mackerel, perhaps acquired while serving in the British Navy, seems to have endured. One of the recurring entries in the books of Morrison, an early merchant of Kaskaskia, is “John Edgar Mackerel"
Burial is unknown
memorial placed here with other residents of Kaskaskia of that time period. Friends of John Edgar were Capt. William Morrison and Lt. Gov. Pierre Menard