The Leon River, part of the Brazos River system, rises at the confluence of its North, South, and Middle forks east of Eastland in northwestern Eastland County (at 32°23' N, 98°49' W). The South Fork rises northeast of Cottonwood in southeastern Callahan County (at 32°13' N, 99°09' W) and runs northeast for twenty-five miles to its mouth on the North Fork (at 32°23' N, 98°48' W). The North Fork rises at Cisco in northwestern Eastland County (at 32°23' N, 98°59' W) and runs northeast for eleven miles. It forms Lake Brelsford and Lake Eastland near Eastland. The Middle Fork rises six miles west of Eastland (at 32°23' N, 98°56' W) and runs east for six miles to join the other two branches to form the Leon River. The river runs southeast for 185 miles through Eastland, Comanche, Hamilton, and Coryell counties to its confluence with the Lampasas and Salado rivers to form the Little River (at 30°59' N, 97°24' W). The South Leon River, a tributary of the Leon, rises in extreme eastern Brown County (at 31°44' N, 98°39' W) and runs northeast across southern Comanche County to join the main stream (at 31°51' N, 98°22' W). Communities along the river include DeLeon, Gustine, Proctor, Lamkin, Jonesboro, Levita, Gatesville, Fort Gates, and Belton.
In its upper reaches the river crosses rocky hills dotted by post oak and cedar. It is dammed to form Lake Leon seven miles south of Ranger, and Proctor Reservoir three miles west of Proctor in Comanche County. Both reservoirs were completed in the early 1960s. Between the Leon and Proctor reservoirs, the thirty-one-mile section of the river is extremely narrow and shallow, but below Proctor Reservoir enough water is released from the dam to provide recreation. The lower river passes through the scenic Cross Timbers area of Central Texas. Its steep and muddy banks are lined with elm, willow, sycamore, and pecan trees. Mother Neff State Park, in extreme eastern Coryell County, and the Corps of Engineers Park, north of Belton, are on the Leon River.
A Texas stream was named Arroyo De León by Alonso De León in 1689, but that river has been identified as the San Antonio. The Leon River is supposed to have been named by members of the Aguayo expedition in 1721, possibly because the river was in flood. Arnold Cavitt and James Coryell explored the area in 1835, looking for land to settle on, and before 1858 homes stood along the riverbanks. Fort Gates in Coryell County was located on the river eighty miles north of Austin, but flooding detained transportation and disrupted military operations. As the cattle industry developed, a branch of the Chisholm Trail followed part of the river. Ferries and toll bridges operated to allow transportation during flooding, and in 1890 Temple developed a water system to draw water from the Leon. The efforts of the Brazos River Conservation and Reclamation District resulted in construction of dams and reservoirs to provide flood control and water supply for cities and farms in the area.