Rockwall County Texas map
32.90° N · 96.41° W · County seat: Rockwall · 149 sq mi
Rockwall County is the smallest of the 254 counties in Texas. Its 149 square miles sit immediately east of Dallas, with Lake Ray Hubbard filling the western edge and Interstate 30 running the whole width of the county in about fifteen minutes of driving. The name comes from a wall-like underground stone formation that settlers cut into while digging wells in the 1850s.
Centered between the city of Rockwall and the East Fork of the Trinity. The water on the west side is Lake Ray Hubbard; I-30 crosses it on a causeway.
Where Rockwall County is
The county is a compact block on the northeast side of the Dallas–Fort Worth metroplex. Collin County is north, Hunt County east, Kaufman County south and Dallas County west. Those four are its only neighbours, one to each cardinal point, which is unusual — most Texas counties touch six or eight.
Downtown Dallas is about 24 miles west in a straight line; Garland is 13 miles west and Mesquite 14 miles southwest, both of them on the far shore of the lake. Plano lies 19 miles west-northwest. The county is inside the Dallas–Fort Worth–Arlington metropolitan statistical area and inside the 4th congressional district, and it keeps Central Time.
Rockwall County has grown faster than almost anywhere else in Texas for two decades. The 2020 census counted 107,819 residents; the Census Bureau's 2024 estimate puts the figure near 137,000, a gain of more than a quarter in four years.
Cities and towns
| Place | Type | 2020 population in county |
|---|---|---|
| Rockwall (county seat) | City | 47,314 |
| Fate | City | 17,976 |
| Heath (part) | City | 9,626 |
| Royse City (part) | City | 9,154 |
| Rowlett (part) | City | 7,543 |
| McLendon-Chisholm (part) | City | 3,564 |
| Wylie (part) | City | 1,442 |
| Mobile City | City | 140 |
Rowlett and Wylie are mostly in Dallas and Collin counties; the figures above count only the part inside Rockwall County.
Roads
- I-30 – the spine of the county, entering from Garland across the Lake Ray Hubbard causeway and leaving east through Fate and Royse City toward Greenville and Texarkana.
- US-67 – runs with I-30 through the county rather than on its own alignment.
- SH-66 – the older parallel route north of the interstate, through Rockwall and Royse City; it follows the original Bankhead Highway line.
- SH-205 – the north–south road, from Rockwall south to Terrell and north toward Wylie and Lavon Lake.
- SH-276 – heads east from Rockwall past Heath's north side toward Quinlan and Lake Tawakoni.
The rock wall itself
The formation the county is named for is a near-vertical seam of sandstone that runs underground for miles, standing in places like a coursed masonry wall several feet thick. Settlers digging water wells near the townsite in the 1850s struck it, and the name stuck to the town in 1854 and to the county when it was cut out of Kaufman County in 1873. Geologists read it as a natural sandstone dike — sand forced into cracks in the surrounding clay and cemented there — but the wall has been dug up and argued over ever since. Sections are exposed at a few private sites around the city.
Lake Ray Hubbard
Lake Ray Hubbard is a City of Dallas water-supply reservoir on the East Fork of the Trinity River, and its eastern shoreline is the Rockwall–Dallas county line for most of its length. That water accounts for 22 of the county's 149 square miles, or about one square mile in seven. Marinas, the harbour district on the Rockwall side and the I-30 causeway all sit on it, and the lake is the reason a county this small has so much waterfront housing. Heath and Rowlett sit on peninsulas that reach into it.