The Siege of Fort Sackville, also known as the Siege of Fort Vincennes or the Battle of Vincennes, was an American Revolutionary War frontier battle fought in present-day Vincennes, Indiana. In February 1779, an American militia led by Lieutenant Colonel George Rogers Clark defeated the British garrison of Fort Sackville commanded by Lieutenant Governor Henry Hamilton. Clark surprised the fort after a grueling march from Kaskaskia, and following the execution of four Odawa captives, forced Hamilton's surrender. On January 29, Francis Vigo, an Italian fur trader, came to Kaskaskia to inform Clark about Hamilton's reoccupation of Vincennes. Clark decided that he needed to launch a surprise winter attack on Vincennes before Hamilton could recapture the Illinois country in the spring. On February 6, Clark set out for Vincennes with 127 volunteers, nearly half of them French militia from Kaskaskia. Captain Bowman was second-in-command on the expedition, which Clark characterized as a "forlorn hope." While Clark and his men marched across country, 40 men left in an armed row-galley, which was to be stationed on the Wabash River below Vincennes to prevent the British from escaping by water.

The attack on Fort Sackville came as a surprise to Hamilton even though the day before a patrol had captured two Virginians and had seen campfires 12 miles south of the fort. He initially believed that the gunfire was caused by a "drunken frolic of the inhabitants" but after a sergeant was slightly wounded realized the fort was under attack and ordered his men to return fire. British artillery fire was able to dislodge some of Clark's men from their position near the village's church but was otherwise ineffective. The Americans responded by firing through the fort's open portholes, wounding some of the gunners. Clark once again demanded unconditional surrender and swore that should he have to storm the fort, "not a single man should be spared." In celebration of Clark's victory, the Americans fired a salute from a British 6-pounder gun. The salute accidentally ignited some gunpowder charges, injuring Bowman and five others. Bowman died five months later from the severe burns he suffered in the accident. Meanwhile, settlers began to pour into Kentucky after hearing news of Clark's victory. In 1779, Virginia opened a land office to register claims in Kentucky, and settlements such as Louisville were established.o