On their return journey they ascended the Illinois river as far as Lake Peoria; they then crossed the portage to Lake Michigan, and in 1675 Marquette founded a mission at the Indian town of Kaskaskia, near the present Utica, Ill.
Chief of these were Kaskaskia, established near the mouth of the Kaskaskia river, about 1720; Cahokia, a little below the mouth of the Missouri river, founded at about the same time; and Fort Chartres, on the Mississippi between Cahokia and Kaskaskia, founded in 1720 to be a link in a chain of fortifications intended to extend from the St Lawrence to the Gulf of Mexico.
In 1771 the people of the Illinois country, through a meeting at Kaskaskia, demanded a form of self-government similar to that of Connecticut.
The English authorities instigated the Indians to make attacks upon the frontiers of the American colonies, and this led to one of the most important events in the history of the Illinois country, the capture of the British posts of Cahokia and Kaskaskia in 1778, and in the following year of Vincennes (Indiana), by George Rogers Clark, who acted under orders of Patrick Henry, Governor of Virginia.
The Virginia House of Delegates, in 1778, extended the civil jurisdiction of Virginia to the north-west, and appointed Captain John Todd (1750-1782), of Kentucky, governor of the entire territory north of the Ohio, organized as "The County of Illinois"; the judges of the courts at Cahokia, Kaskaskia, and Vincennes, who had been appointed under the British administration, were now chosen by election; but this government was confined to the old French settlements and was entirely inefficient.