Harrison County is located in northeastern Texas along the Louisiana border. Marshall, the county seat and largest town, is 152 miles east of Dallas and thirty-nine miles west of Shreveport. The county's center lies at 32°30' north latitude and 94°30' west longitude. Harrison County comprises 894 square miles of the East Texas timberlands, an area that is heavily forested with a great variety of softwoods and hardwoods, especially pine, cypress, and oak. The terrain is gently rolling, with an elevation ranging from 200 to 400 feet above sea level. Northern and eastern Harrison County, about two-thirds of the total area, is drained to the Red River in Louisiana by Little Cypress Creek, Cypress Bayou, and Caddo Lake. The other third of the county is drained by the Sabine River, which forms a part of its southern boundary. Two soil types, upland sedimentary and lowland alluvial, are found in the county. The former, although not so rich as the alluvial, is primarily a sandy loam noted for being loose and easily cultivated. Mineral resources include oil, gas, and clays that have proved valuable for making bricks and pottery. Temperatures range from an average high of 95° F in July to an average low of 37° in January, rainfall averages slightly more than forty-six inches a year, and the growing season extends 245 days.
Caddo Indians lived in the East Texas timberlands for centuries before the arrival of Spanish explorers in the sixteenth century. Agriculturalists with a highly developed culture, the Caddoes were no match for European weapons and diseases. Consequently, American settlers, who began to arrive in large numbers during the 1830s, had few Indian problems in the area that became Harrison County. The settlement of the area was well under way by the time of the Texas Revolution in 1836. A dozen Americans received land grants there from Mexican authorities in the fall of 1835. After the revolution the area filled up so rapidly that the Congress of the Republic of Texas officially established Harrison County in 1839. It was drawn from Shelby County, organized in 1842, and named for Texas revolutionary leader Jonas Harrison. Marshall, founded in 1841, became the county seat in 1842. The original county boundaries were reduced by the establishment of Panola and Upshur counties in 1846. Since then, with the exception of a small adjustment with Marion County during Reconstruction, they have remained unchanged. Harrison County was settled predominantly by natives of the southern United States who duplicated the slaveholding, cotton-plantation society they had known before moving to Texas. By 1850 the county had more slaves than any other in the state, a distinction that it maintained through the next decade. The census of 1860 enumerated 8,784 slaves (59 percent of the total population), 145 planters who owned at least twenty slaves, and a cotton crop of 21,440 bales. Harrison County was among the richest and most productive in antebellum Texas.
In 1861 Harrison County's citizens overwhelmingly supported secession. The area escaped invasion during the Civil War, but hundreds of its men fought, and the majority of its people were called upon to make at least some material sacrifice. Defeat brought military occupation, the end of slavery, and Reconstruction. White citizens bitterly resented federal authority, especially when it meant enfranchisement of the Black majority and a Republican party county government that continued even after the Democratic party regained control statewide in 1874. African Americans found that freedom did not bring significant economic or educational opportunities. Harrison County was "redeemed"—returned to White Democratic rule—in 1878 when residents formed the Citizen's Party of Harrison County and appealed to voters with the argument that Republican government was too expensive. Amidst charges of fraud and coercion, Citizen's party candidates won the election on a technicality involving the placement of a key ballot box and took firm control of local government. The county has remained politically conservative since Reconstruction. Until 1900 its Black voters returned Republican majorities in national elections, but the Citizen's party controlled county offices. Once Black voters were disfranchised, the county voted solidly Democratic in all elections until 1948. At that point, with the national Democratic party tending toward liberal policies, Harrison County began to support conservative Southerners such as Strom Thurmond in 1948 and George Wallace in 1968, and it began to vote Republican. Dwight D. Eisenhower twice carried the area easily. Lyndon B. Johnson (in spite of the fact that his wife came from the county) barely defeated Barry Goldwater there in 1964, and Republican candidates won in 1980, 1984, and 1988. Democrat Bill Clinton won a plurality of the county's voters in 1992 and 1996, at least partly because independent candidate Ross Perot polled strongly in the area during those elections. But Republican George W. Bush carried the county by large margins in 2000 and 2004.
As in antebellum times Harrison County remained overwhelmingly agricultural and rural from 1880 to 1930. During these fifty years, while the population grew slowly from 25,171 to 48,397, the number of farms rose from 2,748 to an all-time high of 6,802. Cotton continued as the main crop, although it was 1930 before production in a census year surpassed the 21,440-bale crop reported in 1860. Production in 1930 was 33,755 bales (see COTTON CULTURE). The county also retained its Black majority through these years. Blacks constituted more than 60 percent of the total population in every census from 1880 to 1930. Harrison County enjoyed transportation facilities that were better than average for East Texas counties, but its nonagricultural economy expanded slowly from 1880 to 1930. The Southern Pacific Railroad, constructed from Caddo Lake to Marshall before the Civil War, became part of the Texas and Pacific Railway system during the 1870s, and the area was soon linked with Shreveport to the east, Dallas-Fort Worth to the west, and Texarkana to the north. The railroad's shops and general offices for Texas were located in Marshall. The county seat benefited from the railroad and from its position as a retail center for the surrounding area, and by 1930 its population was 16,203, approximately one-third of the county's residents. Manufacturing establishments, located primarily in and around Marshall, employed 2,319 workers in 1930. Nevertheless, a majority of the county's workers were employed in agriculture.
The 1930s and 1940s, years of the Great Depression and World War II, marked the beginning of changes in Harrison County at least as significant as those brought on by the Civil War. Depression hit the county hard. The value of farm property fell 30 percent between 1930 and 1935, and there were almost 1,500 fewer farms in 1940 than in 1930. For the first time, a majority of workers depended on nonagricultural occupations, and unemployment became a problem. During the depths of the depression in 1935, 1,114 heads of families in Harrison County were on government relief. As late as 1940, 850 workers were employed on public emergency works, and another 838 were without jobs. World War II ended the economic disaster of the thirties, but it also brought about a significant emigration of Blacks from the county. Between 1940 and 1950, although they continued to constitute a majority, Blacks decreased by 17 percent in number while Whites increased 8 percent. The total population rose from 48,937 to 50,900 during the 1930s and then fell to 47,745 by 1950. The trends that originated during the years of depression and war continued for another twenty years after 1950. The White population increased, but the number of Blacks declined so rapidly that the county showed an overall population loss in each census, dropping to 44,841 by 1970. Agriculture occupied fewer workers each year, and cotton planting virtually disappeared. The agricultural census of 1978 reported only one farmer growing cotton in the county, which in 1860 had produced the third largest crop in the state. Those who stayed on the land depended on mixed farming and cattle raising; others left the area or moved to town. In 1960 and 1970 a majority of the county's people lived in Marshall. No single industry was dominant. Small-scale manufacturing of metal, wood, and clay products gave employment to nearly half of the work force; retail businesses occupied about 10 percent of workers; oil and gas production employed only a few hundred people.
Between 1930 and 1970, as the county lost population and saw its agricultural economy decline, other developments occurred. First, the automobile revolutionized transportation. Harrison County had only 7,396 motor vehicles registered in 1930. By 1950 the total stood at 12,571, and in 1970 there were 26,912. The county had eighty miles of paved roads on January 1, 1937; by 1970 it was crisscrossed with federal and state highways, including Interstate Highway 20, the major artery from Shreveport to Dallas. Second, rural electrification brought electricity to farms and rural homes. The Panola-Harrison Electric Cooperative, begun in 1937, increased its clientele from 332 customers in 1938 to 2,802 in 1950 and 7,416 by 1970. Oil was discovered in the county in 1928, and the production of petroleum and natural gas would continue to contribute to the area's economy into the twenty-first century. Almost 871,000 barrels of oil and 59,392,335 cubic feet of gas-well gas were produced in the county in 2004; by the end of that year 88,982,056 barrels of oil had been taken from county lands since production began. Finally, education advanced significantly. In 1950 only 23 percent of those aged twenty-five or older were high school graduates. By 1970, however, 42 percent met this standard. Developments during the 1970s indicated that the downward trends of the years since 1930 were being halted and even reversed. After three decades of decline, the population rose to 52,265 in 1980, the largest in the county's history. Whites accounted for this increase. The Black population remained stable in numbers but continued to decline as a percentage of the whole. In 1980 Marshall also reported its largest population ever—24,921. The decrease in the number of farms slowed, while the value of agricultural property rose to more than $100 million. Nonagricultural economic activities, with the exception of retail marketing, remained at 1970 levels through the decade. Retail work, however, employed more than twice as many people in 1980 as in 1970. By the early 1980s county workers earned a total of $434 million per year in retail business, petroleum and lumber processing, pottery manufacture, and other businesses. The growth of Marshall and increasing development along Interstate 20 suggested a trend toward significant commercial development in the county. Advances in education continued, and in 1980, for the first time, a majority of residents aged twenty-five or older were high-school graduates. By 1990 the population had increased to 57,483.
The census counted 67,336 people living in Harrison County in 2014. About 63.7 percent were Anglo, 22.4 percent were African American, and 12.1 percent were Hispanic. More than 73 percent of the residents age twenty-five and older had four years of high school, and more than 15 percent had college degrees. In the early twenty-first century oil and gas production, lumber, and pottery and other manufactures continued to be the key elements of the local economy. More than 23,438,000 cubic feet of pine and more than 4,614,000 cubic feet of hardwood were harvested in the county in 2003. In 2002 the county had 1,116 farms and ranches covering 229,272 acres, 35 percent of which were devoted to crops, 33 percent to woodlands, and 28 percent to pasture. In that year farmers and ranchers in the area earned $12,317,000; livestock sales accounted for $10,614,000 of the total. Cattle, hay, poultry, nursery plants, horses, vegetables, and watermelons were the chief agricultural products. Marshall (population, 24,036), the seat of government, is the county's only sizeable city; other towns include Hallsville (3,894), Waskom (2,155), Karnack (350), Nesbitt (278), Elysian Fields (500), Scottsville (366), Harleton (390), and Uncertain (94). Caddo Lake State Park, Lake O' the Pines, and other lakes provide water recreation, and the county maintains numerous historic sites; Marshall hosts a Fire Ant Festival in October.