Cities
- City of Alpine
- Town of Anthony
- Town of Clint
- City of Dell City
- City of El Paso
- Town of Horizon City
- City of Las Cruces
- Town of Marfa
- City of Presidio
- City of Socorro
- Town of Valentine
- Town of Van Horn
- Village of Vinton
Counties
- Brewster County
- Culberson County
- Doña Ana County
- El Paso County
- Hudspeth County
- Jeff Davis County
- Presidio County
Special Districts
- El Paso Community College
- El Paso County Tornillo Water Improvement District
- El Paso Water Improvement District No.#1
- El Paso Water Utilities Public Service Board
- Horizon Regional MUD
- Lower Valley Water District
Tribes
- Ysleta del Sur Pueblo
School Districts
- El Paso Independent School District
- Presidio Independent School District
Associate Members
- Sul Ross University