On 13 March 1839, the Louisiana Legislature passed the Act that officially created Union Parish, Louisiana from the northwestern corner of Ouachita Parish. Union Parish lies along the Arkansas border, in the upland hills region between the Ouachita and Red Rivers of northern Louisiana. It is located in the exact center of the state, as the north/south Louisiana Meridian bisects the parish. Union Parish consists primarily of gently rolling hills, originally covered with towering loblolly pine trees. In fact, the earliest settlers called the southern portion of the parish the Pine Hills. The beautiful rolling pine-topped hills form a distinguishing feature of the topography and flora of west side of the Ouachita River, notably different than the flat prairies and cane breaks on the east side of the river. Numerous cypress sloughs dot the landscape of Union Parish, especially along the various bayous and creeks that crisscross the countryside. Union Parish has remained something of an isolated and rural area since the earliest European settlement, with a population that has never exceeded 25,000.

The Ouachita River forms the eastern border of the parish, and so Union Parish lies to the immediate west of the Mississippi Alluvial Plain, otherwise known as the Mississippi Delta. Whereas the rich, black ground of the delta region contains some of the most fertile soils on earth, most of Union Parish consists of sandy soil peppered with deposits of red, sticky clay. This distinct soil type led to the development of a culture quite different than that found in the Delta parishes across the Ouachita. The wealthy planters who settled in the alluvial lands between the Mississippi and Ouachita Rivers in the 1790s and early 1800s ignored the pine hills on the west side of the Ouachita. As this area did not lend itself to their plantation culture, they left it to the Choctaw who hunted and fished in the region, and scattered Choctaw villages remained along Bayou Corney in what is now Union Parish until about 1830. As a result, the region that became Union Parish did not experience significant settlement until the latter 1830s, when the government finally completed the process of surveying the lands in region.

Beginning in 1835, the government put the lands in north/centeral on the market for cash purchase by citizens, and over the next quarter century, thousands of middle-class farmers from Mississippi, Alabama, Georgia, and Tennessee flocked to the region that later became the hill parishes of Union, Claiborne, Jackson, Bienville, and Lincoln. These small farmers had extensive experience in cultivating this type of soil, and they cleared fields and began planting cotton as their primary cash crop and "Indian corn," sweet potatoes, and other garden vegetables as the primary sustenance crops. These early settlers primarily worked their lands by themselves, without the use of slave labor. Even the minority of Union Parish farmers who owned slaves only owned a few, as the parish never had any plantations or large slave holders like those in the Mississippi Delta.

The pages below include links to various information on early Union Parish, including biographies of some of the earliest residents, brief articles on the parish history, early post offices, etc.