Map - Sullivan County, Indiana (Sullivan County)

Sullivan County is a county in the U.S. state of Indiana, and determined by the US Census Bureau to include the mean center of U.S. population in 1940. As of 2020, the population was 20,758. The county seat (and the county's only incorporated city) is Sullivan.

Sullivan County is included in the Terre Haute, Indiana, metropolitan statistical area.

On February 25, 1779, Col. George Rogers Clark captured Fort Sackville at Vincennes from the British. About 6 mi west at Pointe Coupee on the Wabash River on March 2, 1779, Capt. Leonard Helm commanding three boats and 50 volunteers from Vincennes captured a reinforcement fleet of seven boats carrying 40 soldiers and valuable supplies and Indian trade goods. This small naval battle completed the destruction of British military strength in the Wabash Valley.

The county's first settlement occurred between 1808 and 1812, by a religious society of celibates known as Shakers. The 400 members of this communal group occupied 1300 acre, 7 mi west of Carlisle.

General William Henry Harrison’s army made its last camp in Sullivan County at Big Springs on September 29, 1811. Harrison used Benjamin Turman's fort as his headquarters. With spring water available, it was an ideal location for 1000 men, including 160 dragoons and 60 mounted riflemen. A Kentucky soldier killed a fellow Kentuckian, Clark, either accidentally or in a grudge fight. The deceased was buried at the top of a hill that became the Mann Turman Cemetery. General Harrison and his troops continued north on the Wea Indiana Trail to build Fort Harrison and then proceeded to the Battle of Tippecanoe.

A War of 1812 military action occurred in September 1812, 3 mi west−southwest of Sullivan County. While escorting supplies from Fort Knox near Vincennes to Fort Harrison at Terre Haute, Sergeant Nathan Fairbanks and approximately a dozen soldiers were ambushed - and most killed - by Indians.

In 1815, Carlisle was founded.

An act of the Indiana legislature dated December 30, 1816, created Sullivan County, with areas partitioned from Knox County. The effective date of the new government was 15 January 1817, with interim commissioners charged to begin organizing the new government in February. It was named for Daniel Sullivan, a prominent frontiersman killed in 1790 by Native Americans while carrying a dispatch between Fort Vincennes and Louisville.

A log courthouse in Merom served as Sullivan County's first county seat from 1819 to 1842. Merom was an important river port and a stop on the stage route known as The Old Harrison Trail. William Henry Harrison's troops camped near here on their 1811 march to the Battle of Tippecanoe.

Pioneer heroine of abdominal surgery Jane Todd is buried in Sullivan County. Born in Virginia in 1763, she and her husband, Thomas Crawford, moved to Green County, Kentucky, in 1805. Suffering from a huge abdominal tumor, she rode 60 mi to Danville, Kentucky, to submit to a never−before−performed surgical procedure. On Christmas Day 1809, Dr. Ephraim McDowell performed the first ovariotomy, in his home. The ordeal lasted 25 minutes. There was no anesthesia. Mrs. Crawford recovered completely and years later came to Graysville to live with her son, Thomas, a Presbyterian minister. She died in 1842 at age 78. The restored McDowell home in Danville, Kentucky, is a surgical shrine.