Not just Big Bend but these sites are also elegiable.
http://www.nps.gov/applications/park...tate.cfm?st=tx
Alibates Flint Quarries National Monument
Fritch, TX National Monument
Amistad National Recreation Area
Del Rio, TX National Recreation Area
Big Bend National Park
The big bend of the Rio Grande, TX National Park
Big Thicket National Preserve
Beaumont, TX National Preserve
Chamizal National Memorial
El Paso, TX National Memorial
El Camino Real de Tierra Adentro National Historic Trail
NM,TX National Historic Trail
Fort Davis National Historic Site
Fort Davis, TX National Historic Site
Guadalupe Mountains National Park
Salt Flat, TX National Park
Lake Meredith National Recreation Area
Fritch, TX National Recreation Area
Lyndon B Johnson National Historical Park
Johnson City, TX National Historical Park
Padre Island National Seashore
Corpus Christi, TX National Seashore
Palo Alto Battlefield National Historic Site
Brownsville, TX National Historic Site
Rio Grande Wild & Scenic River
Southwest Texas, TX Wild & Scenic River
San Antonio Missions National Historical Park
San Antonio, TX National Historical Park