Dallas County Texas map
32.77° N · 96.78° W · County seat: Dallas · 909 sq mi · Central Time
Dallas County holds 2,613,539 people, second only to Harris, in 909 square miles — by total area it ranks 177th of the 254 Texas counties. Almost every acre of it is inside a city limit, and the whole county sits inside the freeway ring built around the Trinity River bottoms.
Centered on downtown Dallas. I-635 arcs across the north and east; I-20 crosses the south; the Trinity runs northwest to southeast through the middle.
Where Dallas County is
The county was organized in 1846 out of land taken from Nacogdoches and Robertson counties, and it was named for George Mifflin Dallas, vice president under James K. Polk — though the attribution has never been settled and other Dallases have been proposed. It is a compact block on the Blackland Prairie with six neighbours: Denton to the northwest, Collin to the northeast, Rockwall to the east, Kaufman to the southeast, Ellis to the south and Tarrant to the west.
The Dallas–Tarrant line is the seam of the Metroplex: the two counties together carry the bulk of an eleven-county metropolitan area, and Fort Worth sits 32 miles west of downtown Dallas along I-30. Nothing in the county is remote. The farthest corner, around Wilmer and Seagoville in the southeast, is under 20 miles from the courthouse.
Cities inside the county
Populations below are the 2020 census count for the part of each place that lies inside Dallas County; several of these cities spill across a county line.
| Place | Type | 2020 population |
|---|---|---|
| Dallas (part) | City · county seat | 1,224,049 |
| Irving | City | 256,781 |
| Garland (part) | City | 246,032 |
| Mesquite (part) | City | 150,069 |
| Grand Prairie (part) | City | 124,906 |
| Richardson (part) | City | 77,201 |
| DeSoto | City | 56,108 |
| Rowlett (part) | City | 55,010 |
| Carrollton (part) | City | 51,346 |
| Cedar Hill (part) | City | 48,525 |
| Coppell (part) | City | 41,959 |
| Lancaster | City | 41,281 |
| Duncanville | City | 40,707 |
| Farmers Branch | City | 35,572 |
Highland Park, University Park, Addison, Balch Springs, Hutchins, Sunnyvale, Cockrell Hill and Wilmer are also incorporated inside the county.
The freeway ring
Dallas County is laid out as a set of nested loops around downtown, with radial freeways running out through each suburb.
- I-35E – splits from I-35 at Denton and runs south past Farmers Branch and downtown Dallas toward Waxahachie and Hillsboro.
- I-30 – the east–west spine: Fort Worth and Arlington to the west, downtown Dallas, then Garland's south edge and Rockwall to the east.
- I-20 – crosses the southern third of the county through Grand Prairie, Duncanville and Mesquite.
- I-635 (LBJ Freeway) – the outer loop across the north side from Irving to Garland, then south to meet I-20 near Balch Springs.
- I-45 – begins at I-30 in downtown Dallas and runs southeast toward Ennis and Houston.
- US-75 (Central Expressway) – north from downtown through Richardson into Collin County.
- US-67, US-80 and US-175 – southwest to Cedar Hill, east to Mesquite and Terrell, and southeast to Kaufman.
- Loop 12 and SH-183 – the inner ring and the airport freeway between Irving and Fort Worth.
- Dallas North Tollway and the President George Bush Turnpike – the tolled pair that carries traffic north through Addison and around the northern suburbs.
The Trinity River and the county's water
The Elm Fork and the West Fork of the Trinity join in the western part of the county, and the combined river then cuts southeast past downtown between two earthen levees roughly a mile apart — the floodway is the reason central Dallas has open ground on its west side. Downstream the Trinity leaves the county toward Kaufman and the reservoirs of East Texas.
Lake Ray Hubbard, on the East Fork, forms the eastern boundary with Rockwall County and gives Rowlett and Garland a shoreline. White Rock Lake, an early municipal water supply on the east side of Dallas, is now a city park with a loop trail. Water covers only about 36 square miles of the county. Roughly 3,519 acres are held in 21 county-owned nature preserves acquired through the Dallas County open space program.
Rail and transit
Dallas Area Rapid Transit runs light rail out of downtown Dallas to Garland, Rowlett, Plano, Carrollton, Irving and the southern suburbs, with buses filling in between. The Trinity Railway Express links Dallas Union Station to Fort Worth on the old Texas & Pacific line, sharing a mid-route transfer at CentrePort near DFW Airport. Dallas Love Field sits inside Loop 12 north of downtown; DFW International straddles the Dallas–Tarrant line at the county's northwest corner. Union Pacific and BNSF freight yards still run through the southern half of the county, which is why the warehouse belt clusters along I-20 and I-45.