Texas is a very large state and the best way to divide it up into birding regions, is to use the geographical, geological and ecological areas, which results in the 9 regions illustrated on the map below.
3 ~ Brush Country, bordered on the west by the Rio Grande River
4 ~ Central Plains
5 ~ Pineywoods
6 ~ Northern Plains, bordered on the north by the Red River
7 ~ Edwards Plateau (Texas Hill Country), bordered on the east by the Balcones Fault zone
8 ~ Panhandle and Western Plains
9 ~ Trans-Pecos - part of the Chihuahuan Desert, west of the Pecos River

1a ~ Upper Texas Coast
- Armand Bayou Nature Center
- Big Thicket Natural Preserve
- Edith L Moore Bird Sanctuary
- Galveston Island State Park
- Gulf Coast Bird Observatory
- Hermann Park & Houston Zoo
- Houston Arboretum & Memorial Park
- Jasper State Fish Hatchery
- Jesse H Jones Nature Center
- Katy Prairie (several areas)
- Lafitte's Cove and Lafitte's Grove
- Lake Jackson Wilderness Park
- Mercer Arboretum/Botanical Gardens
- Sam Houston National Forest
- San Jacinto Battleground SHP
- San Luis Pass County Park
- Stephen F Austin State Park
- Varner-Hogg Plantation State Historical Park
1b ~ Central Texas Coast
- Aransas Pass Community Park
- Connie Hagar Cottage Sanctuary
- Copano Bay State Fishing Pier
- Hazel Bazemore County Park
- Lake Corpus Christi State Park
- Matagorda County Jetty Park
- Matagorda Island State Park
- Padre Island National Seashore
- Port Lavaca Bird Sanctuary