| Business | Phone |
| Ash & Assoc Surveying 516 W Hopkins St A, San Marcos 78666 | (512) 392-1719 |
| Byrn & Assoc Inc 1115 Highway 80, San Marcos 78666 | (512) 396-2270 |
| Charles R Swart Co 1519 Ranch Road 12, San Marcos 78666 | (512) 353-7444 |
| Cmr/Pro-Tech Surveying Group 100 E San Antonio St, San Marcos 78666 | (512) 396-5659 |