It was taken over by Great Britain for fifteen years after the French and Indian War; it then became part of the colonies after the Revolutionary War when the area was ceded to Virginia, titled "the Illinois County of Virginia".

Joseph Barron, an interpreter fluent in several Native American languages, stated in an affidavit that he was present at the "Vermilion Salines" that year.

[6] The area's first settlement was made in 1819 near these saline springs, by the Treat, Beckwith, and Whitcomb.

Most settlers in Vermilion County came from the American South, who had left because of their opposition to slavery.

Lincoln gave the speech in his stocking feet from the balcony of Dr. William Fithian, a prominent local physician.

The Fithian home is now listed on the National Register of Historic Places and serves as the Vermilion County Museum;[8] visitors can see Lincoln memorabilia including a bed in which Lincoln slept.

[13] Lake Vermilion, a man-made 1,000-acre (400 ha) reservoir, is the county's largest body of water, located northwest of Danville.

In some cases, the coming of the railroads helped to define the best locations for settlements, and as a result some existing towns were abandoned.

When Lake Vermilion was created, the town of Denmark was flooded and now lies at the bottom of the reservoir.

[25] Vermilion County is in the humid continental climate region of the United States along with most of Illinois.

Its Köppen climate classification is Dfa,[27] meaning that it is cold, has no dry season, and has a hot summer.

Four railroad lines pass through or into the county, all intersecting in the Danville area; this results in many different railroad crossings throughout the city: The Vermilion Regional Airport is located northeast of Danville.

The Vermilion County Circuit Court is led by Judge Thomas O’Shaugnessy.