The Illinois campaign was a series of events in the American Revolutionary War

American Revolutionary War

The American Revolutionary War , the American War of Independence, or simply the Revolutionary War, began as a war between the Kingdom of Great Britain and thirteen British colonies in North America, and ended in a global war between several European great powers.The war was the result of the...

 (1775–1783) in which a small force of Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

 militiamen

Militia (United States)

The role of militia, also known as military service and duty, in the United States is complex and has transformed over time.Spitzer, Robert J.: The Politics of Gun Control, Page 36. Chatham House Publishers, Inc., 1995. " The term militia can be used to describe any number of groups within the...

 led by George Rogers Clark

George Rogers Clark

George Rogers Clark was a soldier from Virginia and the highest ranking American military officer on the northwestern frontier during the American Revolutionary War. He served as leader of the Kentucky militia throughout much of the war...

 seized control of several British

Kingdom of Great Britain

The former Kingdom of Great Britain, sometimes described as the 'United Kingdom of Great Britain', That the Two Kingdoms of Scotland and England, shall upon the 1st May next ensuing the date hereof, and forever after, be United into One Kingdom by the Name of GREAT BRITAIN. was a sovereign...

 posts in the Illinois country

Illinois Country

The Illinois Country , also known as Upper Louisiana, was a region in what is now the Midwestern United States that was explored and settled by the French during the 17th and 18th centuries. The terms referred to the entire Upper Mississippi River watershed, though settlement was concentrated in...

, in what is now the Midwestern United States

Midwestern United States

The Midwestern United States is one of the four U.S. geographic regions defined by the United States Census Bureau, providing an official definition of the American Midwest....

. The campaign is the best-known action of the western theater

Western theater of the American Revolutionary War

The Western theater of the American Revolutionary War was the area of conflict west of the Appalachian Mountains, the region which became the Northwest Territory of the United States as well as the states of Kentucky, Tennessee, and Missouri...

 of the war and the source of Clark's reputation as an early American military hero.

In July 1778, Clark and his men crossed the Ohio River

Ohio River

The Ohio River is the largest tributary, by volume, of the Mississippi River. At the confluence, the Ohio is even bigger than the Mississippi and, thus, is hydrologically the main stream of the whole river system, including the Allegheny River further upstream...

 from Kentucky

Kentucky

The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...

 and took control of Kaskaskia

Kaskaskia, Illinois

Kaskaskia is a village in Randolph County, Illinois, United States. In the 2010 census the population was 14, making it the second-smallest incorporated community in the State of Illinois in terms of population. A major French colonial town of the Illinois Country, its peak population was about...

, Vincennes

Vincennes, Indiana

Vincennes is a city in and the county seat of Knox County, Indiana, United States. It is located on the Wabash River in the southwestern part of the state. The population was 18,701 at the 2000 census...

, and several other villages in British territory.