The early settlers in this area were mainly Scots-Irish from Virginia and Pennsylvania, who began immigrating to the South Carolina upcountry in the 1750s. Much fighting took place here during the American Revolutionary War, including the battles of Musgrove's Mill (August 18, 1780) and Blackstocks (November 20, 1780). Revolutionary leaders Thomas Brandon (1741-1802) and Joseph McJunkin (1755-1846) were from Union County, as were Confederate generals States Rights Gist (1831-1864) and William Henry Wallace (1827-1905). Secession governor William Henry Gist (1807-1874) made his home at Rose Hill Plantation in Union County, now a state park.

The first white settlers came to Union County from Virginia in 1749 and settled on the Pacolet and Tyger rivers and at Fairforest Creek. In the next few years, other families came from Virginia and Pennsylvania and settled around Brown's Creek and Cane Creek.

According to local historian Jeannette M. Christopher, the years between 1763 and the beginning of the Revolutionary War saw the greatest migration into Union County. People built log cabins, cleared the fertile river and creek bottoms and planted tobacco, flax, corn, wheat, and other grains and grazed their animals. There were few slave owners in the early days of the county.

The city and county of Union got their names from the old Union Church that stood not far from Monarch Mill. For a long time the town of Union was known as Unionville, with the name later being shortened. The church was a place for people of the Methodist, Baptist, and Presbyterian faiths to worship.

During the Revolutionary War, the battle of Musgrove's Mill took place on the Enoree River on August 18, 1780 at the junction of what is now Union, Spartanburg, and Laurens counties. Other battle sites in Union County include Fish Dam Ford and Blackstock's Plantation. Even more are documented - see the link above.

A district court was formed by the General Assembly in the late 1700s in the upper part of the county in a new town named Pinckneyville. Located near the junction of the Broad and Pacolet rivers, Pinckneyville was to be the "Charleston of the Upstate" and its streets were named after streets in that city. Despite settlers, a post office, inns and a jail, the town never caught on and the court was moved to the town of Union. Interested persons can visit the ghost town and see the remains of several old buildings, including the court house.

Thomas Cary Duncan, who founded Union and Buffalo mills, was known as Union County's pioneer capitalist and industrialist. He began his own small railroad company to connect Union and Buffalo, aptly named the Buffalo & Union-Carolina Railroad. Hundreds of families moved to Union County from North Carolina and Tennessee and spent their lives working in these cotton mills.

In the early days of World War I, Union County became famous for being the only county in the nation that did not have a draft because its draft quotas were filled by volunteers.

Union County's industrial base is diverse, including the manufacturing of ball bearings, felt products, bath products, cordage, metal forgings, textile fiber, woven goods, finished textile products, and paper pulp. There also are machine shops and metal fabrication facilities.

Although Union County has no interstate highway, a new four-lane was completed in 1991 to Spartanburg County.

In 1999, Walt Disney Company opened a 500,000 square-foot worldwide distribution center on the Furman Fendley Highway north of Jonesville. The company opened an outlet store for Disney products at the center in 1998.

This section was the original home of the Cherokee Indians and was later settled by immigrants from Virginia and Pennsylvania. In the Revolution the territory of Union County was a battleground in the struggle between the Patriots and the British and Loyalists. Then and always its sons and daughters have been loyal to state and country. The county was formed from the old Ninety-Six District in 1785, and gets its name from "Union Church," erected about 1765 near the present site of the city of Union, and used in common by Episcopalians and Presbyterians. The area is 492 square miles, or 314,880 acres; the population (1920) is 30,372, estimated 1925 at 30,632, less than one per cent being of foreign birth.

Union, the county seat, is the largest municipality, with a population (1920) of 6,141, increased by suburbs to 11,000. Its industries are cotton and hosiery mills, cannery, creamery, cotton oil mill. Several smaller towns and villages are in the county, among them Jonesville, 1,209; Carlisle, 376; Lockhart, Buffalo, and Santuc.

Two railroads traverse the county - the Southern Railway and the Seaboard Air Line Railroad - with a mileage of 82; while there are two intra-county short lines connecting with them. The population is less than 24 hours from New York, 15 from Cincinnati and six from Charleston, the chief port of the state.

Through Union County are 800 miles of public roads, 250 miles being of modern topsoil variety, some of which will soon be hard surfaced. Crossing the county are the great Appalachian and Calhoun highways.

Union county's six large cotton and two hosiery mills consume many times the cotton it produces. There are other manufacturing plants on a smaller scale. Several large water power developments provide electric power for industries.

There are four accredited high schools in the county and a public school is in easy reach of all. In education, as in road building, Union County has made marvelous progress in the past few years.

The county offers a soil that responds richly to cultivation. It is of fifteen distinct varieties from residual upland to alluvial river and creek bottoms, Cecil sandy loam and Cecil clay loam predominating. A wide variety of crops can be successfully grown - cotton, corn and other grains, various forage crops, and truck. With the varied industries of the county and adjacent territory, a ready market is provided for truck and farm products. Cattle, hog and poultry raising are on the increase. On account of the long growing season, a minimum of 210 days but often much longer, livestock can be raised at a good profit, requiring little shelter and short winter feeding.

Farm and domestic demonstration agents are employed and their services are offered to new settlers. Union County invites, and is inviting to, the home seeker. Its situation in the heart of a great textile center means continued industrial development. Its level and slightly rolling lands, well drained and productive, to be had at reasonable prices, mean profit. These advantages added to au excellent geographical location and a splendid climate appeal to those in search of a year-round home of health, happiness, and profit.