Illinois Becomes a Territory
The establishment of the Territory of Illinois on February 3, 1809, marked a significant moment in the region's history, transitioning it from a largely unsettled wilderness to a recognized political entity. Approved by President Thomas Jefferson, the territory encompassed not only present-day Illinois but also parts of Wisconsin, Minnesota, and Michigan, reflecting its vast geographical reach. The area had been explored by Europeans as early as 1673, primarily by French explorers Jacques Marquette and Louis Joliet, who navigated the Illinois and Des Plaines rivers and interacted with the Kaskaskia Indians. The French laid the groundwork for settlement through missions and trading posts, yet substantial population growth did not occur until the British took control after the Treaty of Paris in 1763.
Following the American Revolution, the region became part of the newly formed United States, and the territorial governance structure began to take shape. The Northwest Ordinance of 1787 created a system for managing the territories, and in 1800, the Indiana Territory was formed, which included Illinois. However, Illinois's designation as a territory in 1809 catalyzed significant demographic changes, with the population expanding dramatically over the next decade. This newfound status paved the way for the establishment of a territorial legislature and the adoption of a constitution, ultimately leading to Illinois becoming the 21st state in the Union in 1818.
Illinois Becomes a Territory
Illinois Becomes a Territory
On February 3, 1809, President Thomas Jefferson approved the congressional act that organized the western part of the Indiana Territory as the Territory of Illinois. The new entity extended all the way from the Ohio River to the Canadian border and included all of what is now Illinois, most of what is now Wisconsin, and areas in what are today Minnesota and Michigan.
In 1809 Illinois was for the most part an unsettled wilderness. As early as 1673 the French Jesuit Jacques Marquette and his compatriot Louis Joliet explored part of the region. Returning to Canada after an expedition down the Mississippi River, Marquette and Joliet, on the advice of Indians who inhabited the area, set out on the Illinois River. The Frenchmen followed the Illinois on its northwestern course until they reached the Des Plaines River. Then they proceeded up the Des Plaines to a creek that ran east to a low ridge separating the Mississippi basin from the Great Lakes. A portage across the ridge brought the explorers to the south fork of the Chicago River, and from there they continued eastward to Lake Michigan.
Marquette and Joliet were probably the first Europeans to explore Illinois, and several areas in the state commemorate their visit. A portion of the portage that they discovered in 1673 was later preserved as the Chicago Portage National Historic Site. Marquette and Joliet also recorded seeing the Kaskaskia Indian village on their 1673 journey, and Marquette established a mission at the village in 1675. Although Marquette and Joliet were the first Europeans to visit Illinois, credit for establishing the first European settlements in the area belongs to another French explorer, René-Robert Cavelier de La Salle.
In 1679 La Salle set out to discover the mouth of the Mississippi River. In the course of his explorations, he spent considerable time in Illinois, and he came to realize the strategic importance of the Illinois River, which provides a water route from Canada to the Mississippi River. To guarantee French control of this waterway, he built two forts on the river: Fort St. Louis near Ottawa, Illinois, and Fort Crevecoeur near Lake Peoria. The actual settlement of Illinois proceeded very slowly, however. In Illinois, as well as in other places in the New World, the French devoted their efforts to establishing missions and trading posts rather than towns. However, some of the larger missions and posts eventually attracted permanent settlers. For example, the town of Kaskaskia was established near the mouth of the Kaskaskia River around 1703, and Cahokia was founded a little below the mouth of the Missouri River several years earlier.
Illinois remained under French control for about a century. In 1712, when Antoine Crozat was granted temporary possession of Louisiana, the Illinois River was made its northern boundary; and in 1721 more than half the area of what is now the state of Illinois, as well as other territory, was included in the seventh civil and military district of Louisiana, which was named Illinois. The French, however, concentrated their energies on developing the lower Mississippi valley and never tapped the rich resources of Illinois.
With the Treaty of Paris of 1763, France ceded the territory between the Ohio and Mississippi rivers, including Illinois, to Great Britain. Beginning in 1769, Britain allowed settlers from Virginia and its other seaboard colonies to migrate to the newly acquired lands, and as a result of this policy the population of Illinois slowly grew between 1769 and 1774. Then, in 1774, Parliament passed the Quebec Act. The act, which annexed all the territory north of the Ohio River and east of the Mississippi River to the Province of Quebec, and recognized the validity of French civil law in Quebec, deeply antagonized the English colonists. As a result, migration to Illinois and the other areas of the Northwest came to a halt.
During the American Revolution the predominantly French population of Illinois supported the British; nevertheless, the patriots were able to score a number of notable victories in the area. In January 1778 Governor Patrick Henry of Virginia gave George Rogers Clark command of an army of 175 men. Clark and his army surprised and defeated the British at Kaskaskia and Cahokia in the summer of 1778, and by the fall of that year won control of the entire Illinois country. Clark's victories in Illinois and at Vincennes, Indiana, in 1779 were especially important because they helped establish the American claim to the Northwest in the peace negotiations with the British that concluded the American Revolution in 1783.
As a result of the Treaty of Paris of 1783, Illinois came under the jurisdiction of the new American nation. The status of Illinois and the other areas in the Northwest caused a considerable problem. Several states claimed the Northwest Territory because their colonial charters set their western boundaries at either the Mississippi River or the Pacific Ocean. The dispute over land claims even threatened the ratification of the Articles of Confederation, but in 1781 Virginia agreed to cede its western territories to the national government, and by 1786 the other states with western claims had followed Virginia's lead. The following year Congress approved the Northwest Ordinance, which established a territorial government for the area north of the Ohio River.
In 1800, the Indiana Territory was organized, and the Illinois country was included in this new jurisdiction. Illinois remained a part of the Indiana Territory until February 3, 1809, when the Territory of Illinois was established. Gaining territorial status was a watershed in Illinois history: Before 1809 only a few thousand people had settled in the area, but between 1810 and 1820 the population of Illinois multiplied fivefold. With congressional approval, a territorial legislature was chosen in 1812, and a constitution was adopted by the people of the area the same year. In 1818 Illinois was admitted as the 21st state in the Union.