In 1854 the legislature established Coryell County and named it in honor of frontiersman James Coryell, an early landholder. Residents chose the site for Gatesville, the county seat, in an election held in May 1854.
Besides Fort Gates, settlements established in Coryell County in the 1850s included Mound, Coryell Church, Rainey's Creek (Coryell City), Langford Cove (Evant), Boyd's Cove (Bee House), the Grove, Henson's Creek, Spring Hill, Station Creek, Turnover, and Lincolnville.
The majority of residents were from the Old South. Of the heads of households in 1860, the largest number (115) were from Tennessee, forty were from Alabama, and thirty-seven each from Kentucky and North Carolina.
Two railroads were completed through Coryell County in 1882: the Texas and St. Louis Railway laid a narrow-gauge track from Waco to Gatesville, and the Gulf, Colorado and Santa Fe crossed the southern tip of the county near Copperas Cove, making its way from Belton to Lampasas. The arrival of the railroads prompted the establishment of Oglesby, Lime City, and Leon Junction, and provided new economic opportunities for Mound, Gatesville, and Copperas Cove.
Like most areas in the South, Coryell County suffered a severe economic decline after the Civil War and throughout Reconstruction. Between 1864 and 1866 the county lost 63 percent of its tax base. About a third of the lost property was in slaves; the rest came from declines in farm acreage, farm value, and livestock value, each of which had fallen 30 to 50 percent by the time of the 1870 census. Recovery was slow because transportation was poor and the economy was so dependent on stock raising and farming.