John Heery of Milton, Wisconsin walked to the Shell Rock Valley, then back to Dubuque, and on November 22, 1850, filed a claim, part of which is now Heery Wood State Park. He thus became the first landowner but was not among the first settlers, because he did not return with his family until the spring of 1852.
The first settler in the Clarksville area was Joseph Hicks, who came from Rock County, Wisconsin in December 1850 and built a cabin on the north side of what is now Sportsman's Park. Robert T. Crowell helped the Hicks family move but returned to Wisconsin. He returned in 1852 and settled on a farm northeast of town. Mr. Hicks' father Henry, who was a blacksmith, came the following spring and filed a claim for 120 acres near his son. That area at the time was called "Coon's Grove".
On September 16, 1851 Jeremiah Perrin arrived and settled on the farm at the first bend of the road east of town; now the Neal Stauffer home.
On July 6, 1852 the 32 family members of the Clark- Poisal wagon train arrived here after traveling 28 days from Indiana. They set up camp near what is now "The Old Cemetery", decided to stay, built one large log cabin for the whole group to live in, and prepared for the winter. Thomas Clark soon traveled to Dubuque, the nearest land office, and took out claims on a strip of land four blocks wide and running south almost to the river, from what is now Superior Street and east of what is now Main Street.
In May of 1853, it was decided that enough people had settled in Butler County to organize a County Government, so three commissioners were sent here to locate a spot for the County Seat. After, what would seem some rather bizarre events, they drove "the stake" for the site of the Butler County Court House in the block where the old school stood, now post office, library etc. It was agreed that this new village, which didn't even exist yet, would be named Clarksville. To set up the new government an election was held, but no one ran for office, stating that "there was no money in it." The town was surveyed and platted in August 1853, but with no place to record it, they waited over a year for the County government to finally be put in place. On October 27, 1854 the Town of Clarksville was recorded, just after the offices were opened.
The construction of the Courthouse was started in 1856 and finished in 1856 at a cost of $18,000. In 1860, after considerable conflict, the County Seat was moved to Butler Center. Ten years later in 1870, the local school district bought the vacant building for $2,800 and turned it into a schoolhouse.
The town and surrounding area began to grow by leaps and bounds as more and more people arrived, which included both farmers and businessmen, who along with their families, began their life on the new frontier.