Great Plains region of Texas map
One of the 4 natural regions · 1,000 ft to over 4,500 ft · High Plains · Edwards Plateau · Llano Uplift
The Great Plains reach into Texas as a high, dry tableland tilted gently east. Two escarpments define it: the Caprock on the northeast, where the Llano Estacado ends in a cliff, and the Balcones on the southeast, where the Edwards Plateau drops to the coastal plain. In between sits a window of billion-year-old granite, the Llano Uplift.
From the Oklahoma line at the top of the Panhandle south to the Rio Grande at Del Rio, and from the New Mexico line east to the Caprock and the Hill Country.
Where it starts and ends
On the northeast the boundary is the Caprock Escarpment. The Llano Estacado is capped by a layer of caliche — calcium carbonate cemented into rock — that resists erosion, so where streams have cut back into it the plain ends in a wall 200 to 1,000 feet high. It runs from the Canadian River breaks south past Silverton, Floydada, Matador, Dickens and Post. Below it is the Rolling Plains country of the Interior Lowlands. Palo Duro Canyon, cut into that escarpment by the Prairie Dog Town Fork of the Red River, runs about 120 miles and is up to 800 feet deep.
On the southeast the boundary is the Balcones Escarpment. The Edwards Plateau ends abruptly along a fault line through Del Rio, Uvalde, north San Antonio, New Braunfels and Austin; east of it is the Gulf Coastal Plains. The dissected southeastern lip of the plateau, cut into by the Guadalupe, Frio, Nueces and Pedernales rivers, is what Texans call the Hill Country.
On the west the Pecos River closes the region off. Beyond it, ranges rise out of the desert and the map becomes the Basin and Range. The counties in the Pecos valley itself — Loving, Winkler, Ward and Crane — are drawn either way depending on the map.
The three parts
| Part | Elevation | Rain | Ground |
|---|---|---|---|
| High Plains (Llano Estacado and the Panhandle) | 2,700–4,700 ft | 15–22 in | Flat windblown sandy and clay loam over caliche caprock; thousands of shallow playa lakes and no natural drainage over much of it |
| Edwards Plateau | 1,000–3,000 ft | 15–33 in | Thin stony soils on Cretaceous limestone; caves, sinkholes and spring-fed rivers |
| Llano Uplift (Central Mineral Region) | 900–2,000 ft | 24–30 in | Precambrian granite and gneiss about a billion years old, exposed in a rough oval around Llano |
Rain falls off steadily to the west and north: about 33 inches on the eastern edge of the plateau, 18 inches at Lubbock, under 16 at the New Mexico line.
Counties in the region
| Part | Counties |
|---|---|
| Panhandle, north of the Canadian | Dallam, Sherman, Hansford, Ochiltree, Lipscomb, Hartley, Moore, Hutchinson, Roberts, Hemphill |
| Panhandle, south of the Canadian | Oldham, Potter, Carson, Gray, Deaf Smith, Randall, Armstrong, Donley, Parmer, Castro, Swisher, Briscoe |
| South Plains | Bailey, Lamb, Hale, Floyd, Cochran, Hockley, Lubbock, Crosby, Yoakum, Terry, Lynn, Garza, Gaines, Dawson, Borden |
| Southern High Plains and Permian country | Andrews, Martin, Howard, Ector, Midland, Glasscock, Sterling, Upton, Reagan |
| Edwards Plateau | Crockett, Irion, Tom Green, Concho, Schleicher, Sutton, Menard, Kimble, Val Verde, Edwards, Real, Bandera, Kerr, Kendall, Gillespie, Blanco, Kinney, Uvalde, Medina, Comal |
| Llano Uplift | Llano, Mason, San Saba, Burnet, McCulloch |
Cities
- Lubbock
257,141 people (2020) at about 3,200 ft, the largest city on the Llano Estacado and the market town for the cotton country around it.
- Amarillo
200,393 people at roughly 3,600 ft, on I-40 and the old Route 66 alignment, with the Canadian River breaks just north.
- Midland
132,524 people on the southern edge of the Llano Estacado, the office town of the Permian Basin.
- Odessa
114,428 people, 20 miles west of Midland on I-20 and the field-services half of the same oil district.
- San Angelo
99,893 people where the three forks of the Concho meet, on the northern rim of the Edwards Plateau in the Concho Valley.
- Big Spring
26,144 people on I-20 at the break between the High Plains and the plateau, named for the spring that watered the Comanche trail.
- Kerrville
24,278 people on the Guadalupe River in the dissected southeastern plateau.
- Fredericksburg
10,875 people in Gillespie County, between the limestone plateau and the granite of the Llano Uplift.
- Del Rio
34,673 people at the southwest corner of the plateau, where the Devils River and the Pecos reach the Rio Grande at Amistad Reservoir.
Highways
- I-40 – straight across the Panhandle through Amarillo, the busiest road on the High Plains.
- I-27 – Amarillo to Lubbock, the only interstate joining the two High Plains cities.
- I-20 – Big Spring, Midland and Odessa, climbing off the plateau from Abilene.
- I-10 – across the Edwards Plateau through Junction, Sonora and Ozona toward Fort Stockton.
- US-87 – the diagonal from Amarillo through Lubbock, Big Spring and San Angelo to Fredericksburg and San Antonio.
- US-90 and US-83 – the plateau's north–south and east–west back roads, meeting at Uvalde.
- US-287 – the Panhandle diagonal toward Dalhart and the Oklahoma line.
Water, crops and drilling
Farming on the High Plains depends on the Ogallala Aquifer, a body of water-bearing sand under the caprock that is pumped far faster than it recharges. Center-pivot irrigation turned the country around Lubbock into what is usually called the largest contiguous cotton-growing region in the world, along with corn, grain sorghum and winter wheat further north. Cattle feedyards cluster in the northern Panhandle around Hereford, Dimmitt and Dalhart, where the grain is grown, and dairies have moved in beside them. Rain that does fall usually collects in playas — shallow clay-floored basins numbering in the thousands — rather than running to a river.
The Edwards Plateau is too thin-soiled to plough. It carries sheep, Angora goats, cattle and one of the largest white-tailed deer populations anywhere, hunted on leases. Its limestone holds the Edwards Aquifer, which discharges at the Balcones springs and supplies San Antonio.
Drilling dominates the southern end. The Midland Basin under Midland, Martin, Howard, Upton and Reagan counties is the eastern half of the Permian Basin, and the Spraberry and Wolfcamp intervals beneath it are among the most heavily drilled rock in the United States. In the Panhandle, the gas field around Hutchinson and Carson counties is unusually rich in helium, which is why the federal helium reserve was sited near Amarillo.
Distinctive facts
| Highest ground in the region | Over 4,500 ft in Dallam County at the far northwest corner of the Panhandle |
| Largest canyon | Palo Duro Canyon, about 120 miles long and up to 800 ft deep |
| Oldest rock in Texas | Precambrian granite and gneiss of the Llano Uplift, roughly a billion years old |
| Granite dome | Enchanted Rock, rising about 425 ft above the country north of Fredericksburg |
| Capitol stone | Pink granite for the Texas State Capitol was quarried at Granite Mountain near Marble Falls |
| Aquifers | Ogallala under the High Plains, Edwards under the plateau |