A people known as the Bluff Dwellers, who inhabited caves, probably lived in the Arkansas area before 500. They were followed by the Mound Builders, who received their name from the mounds they constructed, apparently for ceremonial purposes. The first Europeans to arrive in Arkansas (1541–42) were probably members of the Spanish expedition under Hernando De Soto. Later the French explorers Jacques Marquette and Louis Jolliet came S along the Mississippi to the mouth of the Arkansas River. A number of Native American groups, such as the Osage, Quapaw, and Caddo, lived in the vicinity.
In 1682, Robert La Salle's lieutenant, Henri de Tonti, established Arkansas Post, the first white settlement in the Arkansas area. La Salle claimed the Mississippi valley for France, and the region became part of the French territory of Louisiana. The French ceded the Louisiana territory to Spain in 1762 but regained it before it passed to the United States under the Louisiana Purchase (1803).
Arkansas became part of the Territory of Missouri in 1812. The cotton boom of 1818 brought the first large wave of settlers, and the Southern plantation system, moving west, fixed itself in the alluvial plains of S and E Arkansas. In 1819 the area was made a separate entity, and the first territorial legislature met at Arkansas Post. The capital was moved to Little Rock in 1821. Arkansas achieved statehood in 1836.
As the Civil War began, poorer farmers were generally indifferent to questions of slavery and states' rights. The slaveholding planters held the most political power, however, and after some hesitation, Arkansas seceded (1861) from the Union. In the Civil War, Confederate defeats at Pea Ridge (Mar., 1862), Prairie Grove (Dec., 1862), and Arkansas Post (Jan., 1863) led to Union occupation of N Arkansas, and General Grant's Vicksburg campaign separated states W of the Mississippi from the rest of the Confederacy. In Sept., 1863, federal troops entered Little Rock, where a Unionist convention in Jan., 1864, set up a government that repudiated secession and abolished slavery. Because the state refused at first to enfranchise former slaves, Arkansas was not readmitted to the Union until 1868, when a new constitution gave African Americans the right to vote and hold office.
Reconstruction in Arkansas reached a turbulent climax in the struggle (1874) of two Republican claimants to the governorship, Elisha Baxter and Joseph Brooks. Baxter's apparent success in the election was not accepted by Brooks, and followers of the two men resorted to violence in what became known as the Brooks-Baxter War. After President Ulysses S. Grant declared Baxter to be governor, Baxter called a constituent assembly dominated by Democrats to frame a new state constitution. The convention adopted (1874) the constitution that, in amended form, still remains in force.
During Reconstruction the so-called carpetbaggers and scalawags were detested by most Arkansas whites, but their administrations brought advances in education and (at exorbitant costs caused by corruption) railroad construction. Because of high cotton prices and the failure to give the freed slaves any economic status, the broken plantation system was replaced by sharecropping and farm tenancy. The lives of the people of the Ozarks remained largely unchanged; they retained the customs, skills, and superstitions that have given the hill folk their distinctive regional characteristics. In the late 19th cent., as railroad construction proceeded, Arkansas's population grew substantially, and bauxite and lumbering industries developed. Oil was discovered in Arkansas, near El Dorado, in 1921.
Disaster struck in 1927 when the Mississippi River overflowed, flooding one fifth of the state. With the fortunes of the state pegged to the price of cotton, the depression of the early 1930s (see Great Depression) struck hard. Dispossessed tenants, black and white, formed (1939) the Southern Tenant Farmers Union; after trouble with the authorities, it moved its headquarters to Memphis, Tenn. A strike called in 1936 spread to other regions before its strength waned. Other impoverished farmers migrated west to California as "Arkies"—like the "Okies" from neighboring Oklahoma. After World War I, African Americans left the state in a steady stream to the industrial North. World War II brought further loss of population as workers left Arkansas for war factories elsewhere. The war, however, created a boom for new industries in the state, notably the processing of bauxite into aluminum.
The decline of industrial output after the war was offset by the vigorous efforts of a state development commission formed in 1955 to attract new industry to Arkansas. Governor Orval Faubus of Arkansas became a center of national and world attention in 1957 when he resisted the desegregation of public schools in Little Rock (see integration). Arkansas has long been dominated by the Democratic party, but in 1966 Winthrop Rockefeller (see under Rockefeller, John Davison was elected the state's first Republican governor since Reconstruction. Although reelected in 1968, Rockefeller lost the governorship to a Democrat, Dale Bumpers, in 1970.
In 1971, Arkansas and Oklahoma joined in the Arkansas River Navigation System, a project that developed the Arkansas River basin to provide water transportation to the Mississippi. In the early 1990s, the Arkansas-based Wal-Mart merchandise chain, founded by Arkansan Sam Walton in 1962 as a small-town discount store, became the largest retailer in the United States. Bill Clinton, the governor of Arkansas (1979–81, 1983–92), was elected president of the United States in 1992. In the mid- to late 1990s national attention focused on Arkansas as Clinton associates, including Jim Guy Tucker, his successor as governor, were embroiled in Whitewater and other scandals.