May 1, 2025 is Illinois History Day! Illinois was discovered in 1673 by explorer Louis Jolliet and Jesuit Father Jacques Marquette when they floated down the great Mississippi, returning up the Illinois River and crossed the portage to Lake Michigan where Chicago now stands.

Cahokia, Illinois' first permanent European settlement, was established in 1699 along the Mississippi River across from what is now St. Louis. The French and Indian War, or Seven Years' War, came to an end in 1763 with a victory for Britain, which gains control over the Illinois country. With the end of the American Revolution in 1783, Illinois became territory of the United States − technically part of the state of Virginia. Illinois would later join the Union on Dec. 3, 1818 – becoming the 21^st state.

In 1804, Lewis and Clark's Corps of Discovery spent the winter in Illinois, near present-day Wood River, to train and prepare for their cross-country journey and then depart in May. Fourteen years later, the state's first bank opened at Shawneetown. The town, center of the territory's lucrative salt-making industry, later became home to the Bank of Illinois. Vandalia, founded in 1819 specifically to replace flood-prone Kaskaskia as the state capital, officially became the seat of government.

In 1860, Abraham Lincoln was nominated for president in Chicago after his top aides cut deals and pack the "Wigwam" convention hall. Lincoln went on to win the presidency of a country that is falling apart. In 1871, the Chicago Fire destroyed 18,000 buildings, killing about 300 people and leaves one-third of the city's residents homeless. The fire did indeed start in the barn of a Mrs. O'Leary but a reporter invented the story that it was started by a cow kicking over a lantern. Rebuilding from the fire triggered a period of growth and innovation for Chicago.

On Illinois History Day we honor and celebrate Illinois’ long treasured history since its discovery in 1673.