In 1803, most of the land for modern day Kansas was acquired by the United States from France as part of the 828,000 square mile Louisiana Purchase for 2.83 cents per acre.

During the Civil War the Kansas legislature ordered the survey of western two-thirds of the new state in anticipation of future settlement.

An escort of soldiers from Fort Riley accompanied U.S. Deputy Surveyors D. E. Ballard and E. C. Manning as they commenced the survey of what is now Osborne County on September 8, 1862.

Early the next year, however, they had to suspend their surveying efforts due to the proximity of, and objections from, the natives of the area - the Indians.

Several Indian tribes had hunted in the valley for decades and were in no mood to share the land with settlers bent on decimating the abundant game, plowing under the lush grass for farming, and just generally changing the way things were.

While escorting the surveying party along Twin Creek on July 21, soldier Edward Roche of Company I, 2nd U.S. Cavalry, was killed by Indians.

The governor named it in honor of Captain Vincent B. Osborne, a Civil War soldier who lost a leg in a battle on January 17, 1865, at Joy's Ford on the Arkansas River.

Both men were members of the Rotterdam Dutch Colony that settled in 1869 and 1870 along Oak Creek in what are now Mitchell, Osborne, Jewell, and Smith Counties.

That same month brothers Charles and William Bullock made the first permanent non-native settlement in the county on the north side of the South Solomon River in what is now Tilden Township.

They constructed a double cabin with port holes surrounded with a log enclosure for their horses and the "Bullock Ranche" became the terminus for all early homestead and hunting parties in northwest Kansas over the next two years.

The first couple married in the county, Solomon Weatherman and Marinda Alling, had to travel to Beloit to obtain a marriage license before returning to their homestead two miles south of modern-day Bloomington.

The second town in Osborne County, Arlington, was founded when Calvin Reasoner opened a log general store two miles east of present-day Bloomington in late 1870.

B. Fleming was appointed to ascertain whether the county held the 700 residents required for securing state recognition of legal organization, and it was decided to reconvene one week later on Saturday, June 3, 1871, at Arlington with the results.

"He [Reasoner] sent runners north, south, and west, notifying them to be at Arlington at seven p.m. that day for the purpose of locating a county seat.

Our men started at once, north, east, and south, telling every one to meet here at six p.m., that the county seat was to be located.

The census committee reported 724 inhabitants and 281 voters in the county, a sufficient number under law to further proceed with organization.

We have never heard of the town!’ Our president then arose and deliberately drew from his pocket the charter of Osborne City, containing the great seal of the secretary of the state of Kansas, which he exhibited to the audience.

B. Fleming, and Charles Bullock were appointed to draft a petition to the governor praying for recognition of Osborne County's legal organization.

This was done and on September 12, 1871, Kansas Governor James Harvey issued a proclamation declaring the county organized and a legal entity.

Only six of 27 Democratic presidential candidates since 1920 have reached so much as thirty percent of Osborne County's vote – the last of these being Michael Dukakis in 1988 during a major Great Plains drought.