Rockwall County's first Anglo-American settler arrived in 1846

John O. Heath arrived in 1846 along the East Fork of the Trinity River, becoming the area's first Anglo-American settler. He received a grant through the Mercer colony and established his home near the crossing of the Central National Road. By 1852 a Baptist church had been established. The area's first post office was known as Black Hill; it moved to the new village of Rockwall in 1855.

The National Road of the Republic of Texas ran through the region in the mid-1840s, connecting the Red River to present-day Dallas. This route helped early settlers find their way into the area. Cattle ranching was the main livelihood in those first years, with small farming operations scattered along the river.