Randolph County, the largest county in West Virginia with an area of 1,040 square miles, is located at the western edge of the Potomac Highlands in east-central West Virginia. Its high, forested mountains, many of which exceed 4,000 feet, lie at the headwaters of the Cheat, Tygart Valley, Elk, and Potomac rivers. The highest point in the county is in its extreme northeast corner on the Roaring Plains, a level area of land next to Dolly Sods, with an elevation of 4,782 feet. The lowest point is at 1,800 feet, at Laurel, where the Tygart Valley River leaves Randolph County for Barbour. Shavers Fork of Cheat River, which bisects Randolph County, enters the county at an elevation of 3,700 feet and leaves it at 1,765 feet.

The earliest settlements were those of the Robert Files (Foyles) and David Tygart families, who settled near present Beverly and Dailey in 1753—54. Most of the Files family were massacred by the Indians, and the Tygart family fled within a few months. By 1772, settlers had claimed most of the prime valley lands, but the continuing incursions of Indians deterred widespread settlement. A series of forts, including Wilson's, Roney's, Friend's, Hadden's, Currence's, and Westfall's, were built in the 1770s under the direction of frontiersman Benjamin Wilson. These forts offered some protection, but more than 100 settlers lost their lives in Indian raids during a period of 20 years.

Randolph County was formed from Harrison County in 1787 and was named for Edmund Randolph, governor of Virginia and later attorney general and secretary of state of the United States. The county seat was established at Edmundton in 1787. Edmundton was renamed Beverly and chartered in 1790. Beverly remained the county seat of Randolph County until the government was moved to Elkins in 1899, following a protracted and strongly contested legal battle for the location of the courthouse.

Farming was the principal livelihood for the settlers who had occupied the level terrain of the Leading Creek drainage and the broad bottomlands of the Tygart Valley River. These bottomlands extend 35 miles along the meandering river from Valley Head to Leadsville (Elkins). The coming of the early turnpikes brought some commercial activity, but the turmoil of the Civil War stunted development.

Most Randolph Countians preferred the Southern cause when the Civil War split the nation. The county voted in favor of secession when Virginia left the Union in 1861. Residents served on both sides during the bloody conflict, with most joining the Confederate forces. Some of the earliest action of the war took place in Randolph County. The Battle of Rich Mountain occurred five miles west of Beverly on July 11, 1861, when Gen. William S. Rosecrans routed the Confederate troops led by John Pegram. Other significant conflicts and fortifications were at Laurel Hill, Beverly, Huttonsville, Elkwater, Valley Mountain, and Cheat Mountain. Both Union Gen. George B. McClellan and Confederate Gen. Robert E. Lee received their early combat experience of the Civil War in Randolph County.

Since the turn of the 20th century, the county has been a major producer of hardwood lumber. There are extensive lumber and woodworking operations in Elkins, Beverly, Dailey, Mill Creek, Norton, and other areas. In 2005, Randolph County produced 61.3 million board feet of hardwood lumber and thousands of tons of pulpwood and rustic fencing. Some of this production came from the 202,000 acres of national forestland in the county.

Railroads played a vital role in the economic growth of Randolph County after industrialists Henry Gassaway Davis and his son-in-law, Stephen B. Elkins, extended the West Virginia Central & Pittsburg [sic] Railroad to Leadsville in 1889. They later constructed the Coal & Coke Railroad to Charleston. Within a decade, major railroad extensions provided the county with a direct connection with the main line of the Baltimore & Ohio Railroad. This offered a nationwide market for the county's abundant timber and coal. The Western Maryland Railway Maryland Railway and the Chessie System continued to serve the county until the 1980s, when the CSX Railroad ended its service to the region. The West Virginia Railroad Authority now serves Randolph County.

With the coming of rail transportation, mining Randolph County's vast coal reserves became an important economic activity and remained so for many years. Coal production was 884,735 tons in 1920 and peaked at 1,237,000 tons in 1980, but had dwindled to practically nothing by 2004. In 2005, the county still had an estimated coal reserve of 2,416,000,000 tons.

The Elkins-Randolph County Airport, constructed in 1934—35, served as a terminal for major and commuter airlines for a half-century and is now the home port for many private and corporate aircraft. An automated flight service station operated by the U.S. government at the airport provides updates on weather and flight data for aircraft entering into the air space of West Virginia.

Davis & Elkins College, founded in Elkins in 1904, was named in honor of its two patrons, Henry Gassaway Davis and Stephen B. Elkins. The college is a four-year liberal arts institution affiliated with the Presbyterian Church. Other long established institutions are the West Virginia Children's Home and the West Virginia Odd Fellows Home.

Agencies of federal and state governments maintain a strong presence in Randolph County. The Monongahela National Forest, with almost 909,000 acres in ten West Virginia counties, is headquartered in Elkins. The U.S. Fish and Wildlife Service and the West Virginia Division of Natural Resources administer and provide research in managing game and wildlife in the region. At Huttonsville, the state maintains the Huttonsville Correctional Center which houses an inmate population of about 900.

Randolph County became a haven for European families seeking land and opportunity in the United States in the 1880s. Several Irish families settled at Kingsville in 1845—60, and an English colony was established at Mingo Flats in 1883—95. Swiss immigrants were lured to the county in large numbers and established communities at Helvetia, Alpena, and Adolph during the period of 1869—81. The original settlers of the county included Germans and many Scotch-Irish.

Randolph County had 484 operating farms in 2007, with 104,441 of the county’s 665,424 acres classified as farmland. There were 233 cattle farms, 20 hog farms and 57 sheep farms sustained by more than 16,000 acres of corn and hay production. The population of the county was an estimated 29,384 in 2012. Prominent Randolph Countians include Davis and Elkins, both U.S. senators as well as industrialists, and Senators Howard Sutherland and Jennings Randolph. Gov. Herman Guy Kump was a Randolph Countian, as was Gov. William W. Barron. Football player Marshall "Biggie" Goldberg began his sports career at Elkins High School.