In the Pre-Colonial era, the River Valley was inhabited by Native American tribes, including Caddo, Cherokee, Choctaw, Osage, Tunica, and Quapaw tribes. Most first encounters describe scattered villages and individual farmsteads in the River Valley, unlike the organized "towns" and groves and orchards encountered in eastern Arkansas. Much of what is known about these early societies has been uncovered by the Arkansas Archaeological Survey and the Arkansas Archaeological Society at Carden Bottoms in Yell County near the Arkansas and Petit Jean Rivers. Research at the site has linked artifacts to cave art (pictured at right) in a cave on Petit Jean Mountain, as well as establishing links to the Caddo, Osage, and Quapaw tribes.
Hernando de Soto became the first European explorer to enter Arkansas in 1541. His expedition of 600 Spanish explorers searching for gold and riches crossed into Arkansas across the Mississippi River, and explored the state for the next two years. The expedition traveled to Tanico, an important city somewhere in the River Valley, in September 1542. The following month, the expedition fought with a tribe referred to as the Tula somewhere near Fort Smith. This fighting apparently caused de Soto to turn the expedition back east, leaving the River Valley.
Following the war, the Southern economy was in shambles, including Arkansas. The cost of the war effort, loss of human capital, and Confederate currency losing value were serious issues for the South in addition to the destruction of property, infrastructure, and crops. Many parts of Arkansas had descended into lawlessness and violence between whitecapping groups (including the Ku Klux Klan), freedmen, Republicans, and unaffiliated bandits taking advantage of the chaos. Indicative of the disarray, Radical Republican Governor Powell Clayton declared martial law in ten counties following reelection in 1868. Although no River Valley counties were initially subject to the proclamation, Clayton added four more counties, including one partial-River Valley county, Conway County. Since settlement, the River Valley had been a largely cashless society with significantly less reliance on slave labor compared to plantation agriculture areas like the Arkansas Delta and elsewhere in the Deep South. The Klan had limited support, and much of the area was viewed steadily Re Due to its relatively strong position following the Civil War, the River Valley attracted new settlement throughout Reconstruction. Populations of Austrian Catholics, German Catholics, and Lutherans were relocating to the River Valley. Some immigrated directly from Europe, but most came from early settlements in the Ohio River Valley. The Lutherans generally immigrated in organized companies, where the Catholics came independently, although some Catholic settlements like Clarksville and Subiaco were founded by organized groups. These settlements received support from existing immigrant populations in Little Rock and Fort Smith, and groups of Protestant settlers also establishing settlements in the area. Several of the River Valley's small towns were founded by these groups, beginning as small clusters of immigrants and evolving into cohesive communities.
Many immigrants came to the River Valley searching for agricultural prosperity, particularly by farming cotton, which could fetch high prices at market and quickly turn a farm into a profitable enterprise. Upon arriving in the region, many found only densely forested upland to be the only property they could afford. River Valley soil and climate are much less conducive to cotton cultivation than the Arkansas Delta, and many settlers struggled. Eventually, a preference for mixed farming emerged, including potatoes and other garden vegetables, to protect against a poor cotton crop sending a farm into economic ruin.