Henry County was under Knox County until 1837. It was organized as a county on March 2, 1837. George Brandenburg settled at what became Dayton (now Dayton Corners housing sub division, near Colona) near the Rock River. This area was a stage coach stop. The town was laid out earlier in October 1836. A group of Protestant ministers organized the Connecticut Association to settle the Midwest when they heard Catholic settlers were moving in that direction.

A New York organization was also formed. Reverend Ithamar Pillsbury, Mr. Slaughter, and Mr. Pike came to the area where a Dr. Baker had a log cabin. Dr. Baker moved away but the gentlemen laid out the town of Andover in 1835 and purchased a large quantity of land.

Wethersfield and Geneseo were settled in the fall of 1836. The railroad came through in 1854 and Kewanee was laid out 2 miles north of Wethersfield. The towns of Kewanee and Wethersfield combined and became Kewanee in 1924.

Col. Blish, Mr. Goodrich, Mr. Little, Mr. Willard, and Mr. Tenney led the settlers. It cost $90 per person for the trip from Boston to Rhode Island by rail, boat to New York, rail to Pennsylvania, by canal to Pittsburgh, down the Ohio River to the Mississippi River, up the Illinois River to Peoria, then across the prairie to Wethersfield.

Andover and Wethersfield were laid out like New England towns. There were 16,000 acres in the Wethersfield colony.

Geneseo was settled by a group from New York. Mr. Stewart, Mr. Bartlett, and Mr. Ward came to look for land. They settled by Geneseo Creek. Land was $1.25 an acre. The first settlers came by covered wagon from the town or Bergen, New York to Buffalo, and they crossed at Niagara Falls along Lake Erie on the Canadian side, then down to Detroit, onto Joliet, Princeton, and Wethersfield and finally to Geneseo where no cabins were ready.

Richmond and Morristown and many other small settlements were laid out but no longer exist. Richmond was the first County seat from 1837 - 1842. Morristown was the second County seat from 1842 - 1844. Cambridge was the third and final County seat from 1844 to the present.

The land was very fertile and good for farming. There were also many coal mines north of Kewanee giving many people employment.

Cambridge was settled in 1843, Colona in 1855, Galva in 1853, and Woodhull in 1857.