Region 12 San Antonio Flood Planning Region

The Medina river originates in Northwestern Bandera county on the Edwards Plateau where it flows southeast to merge with the San Antonio River, flowing from its spring-fed headwaters in Bexar County, just southeast of the City of San Antonio. From there, the San Antonio River flows across the South Texas Plains largely unimpeded where it empties into the Guadalupe River just northwest of San Antonio Bay. Other streams within the basin include the Leon, Salado, Calaveras, and Cibolo creeks. This region crosses five ecoregions and is home to three major lakes and reservoirs.

For a detailed map of Region 12, please visit the Texas Geographic Information Office (TxGIO) Flood Planning Regions Map Collection.

Go to Region 12 San Antonio RFPG External Host Website

Population Estimate (2019): 2,225,430

Approximate Area: 4,422 square miles

Approximate Stream Miles: 4,206

Approximate NFIP Claims (1975-2019): $48,925,054

Counties Represented:

• Aransas*
• Atascosa*
• Bandera*
• Bexar*
• Calhoun*
• Comal*
• De Witt*
• Goliad*
• Guadalupe*
• Karnes*
• Kendall*
• Kerr*
• Medina*
• Refugio*
• Victoria*
• Wilson*

*indicates this county is partially within this RFPG and is also represented by at least one other RFPG

Major Cities (Population greater than 25,000):

• Cibolo*
• Converse
• New Braunfels*
• San Antonio
• Schertz*
• Timberwood Park

*indicates this city is partially within this RFPG and is also represented by at least one other RFPG

Major Lakes & Reservoirs:

• Calaveras Lake
• Medina Lake
• Victor Braunig Lake

Ecoregions of Texas Represented:

• Blackland Prairie
• Edwards Plateau
• Gulf Prairies
• Post Oak Savanah
• South Texas Plains