Joint Base San Antonio (JBSA) comprises three non-contiguous military installations, one sub-installation in Bexar County, and one auxiliary airfield in Guadalupe County. JBSA is made up of:
- JBSA-Fort Sam Houston located near downtown San Antonio with its sub-installation JBSA-Camp Bullis located in northern Bexar County.
- JBSA-Lackland located in west Bexar County and the City of San Antonio, and
- JBSA-Randolph located in northeast Bexar County and its auxiliary airfield located in Guadalupe County about seven miles south-southeast of the City of Seguin.
The expanse of JBSA and its influence area is illustrated in the map below. The installations are surrounded by varying degrees of development. A significant portion of JBSA-Lackland including the Medina Training Annex is located adjacent to rural / agricultural land uses while the other portions of JBSA-Lackland are surrounding by urban development from the west side of the City of San Antonio. JBSA- Randolph proper is mostly surrounding by suburban development where uses are a mix of rural residential, commercial, retail, and urban development. However, JBSA-Seguin Auxiliary Airfield located in Guadalupe County is surrounded by unincorporated area that is characterized by agricultural land uses. Finally, JBSA-Camp Bullis, the sub-installation of JBSA-Fort Sam Houston, is located in north Bexar County surrounded by both urban development and rural and agricultural land uses.
The JBSA RJIS Planning Area was designed to encompass all operational areas of the JBSA, as well as all lands in the vicinity that may impact current or future military operations or be impacted by those operations.