The East Central Indiana territory which became Randolph County was first settled by Quakers from North Carolina in 1814. Randolph County came off the north end of Wayne County and was officially established by the Indiana Legislature in 1818, the twelve original county. Winchester was at that time chosen as the site of the county seat and was also the main post office between Richmond and Fort Wayne which was in organized Randolph County at that time. In 1824 Allen County was formed leaving "Salamonie Township", consisting of present Adams and Jay Counties, until 1836 when these counties were formed.

Because they were Quakers, some early settlers helped establish a school for free black students as well as white. There were three predominantly black settlements in Randolph County. The school, the Union Literary Institute, was in southeastern Randolph County and funds from its original establishment by landowners who were black still exist today. Much historic material has been collected on this, the first school of its kind in Indiana and perhaps the country. Three museums in the county and many good private collections of historic papers and memorabilia exist in the country.

Randolph County contains 456.75 square miles, has a population of 27,364 people by the 2001 census. The county has 874.11 miles of county roads, well cared for and mostly paved, with a total of 221 county bridges. There are many miles of county ditches in the county due to the fact it is essentially a plateau with the Whitewater River, White River and the Mississinewa, beginning here and flowing and draining in different directions, leaving almost swampy conditions in certain areas.

Randolph County is on the Indiana-Ohio State Line and has one city, Union City, in both states, half in each one, with separate city governments and what is confusing, two separate time zones. It is located at the intersection of two major highways - U.S. highway 27 which travels north and south and Indiana highway 32 that extends east and west. Located near the center of the nation's heartland, Winchester is 220 miles southwest of Chicago, 320 miles northeast of St. Louis, 90 miles north of Cincinnati, 85 miles east of Indianapolis, 60 miles northwest of Dayton and 230 miles south of Detroit. Well over half the nation's population lives within commercial access of Winchester.

Randolph County is both an agricultural county and an industrial county. Agriculture consists of mostly raising corn and soybeans, but also has nationally and internationally known livestock breeders. The industrial community consists of automotive-related businesses and glass manufacturing businesses. Union City Body Company, the foremost producer of forward drive vans, had a 100th anniversary celebration in November, 1997, most of that period of time owned by one family. Anchor Glass has a state-of-the art plant in Winchester which has won many awards for its production. Tours of this plant are often scheduled for groups.

The largest attraction by attendance in the county is the Winchester Speedway. It is the world's fastest half-mile banked track oldest in Indiana. More than 100,000 visitors attend the track annually.