San Carlos is a community and census-designated place (CDP) in Hidalgo County, Texas.

[3] According to the United States Census Bureau, the CDP has a total area of 1.8 square miles (4.7 km2), all land.

San Carlos is five miles east of Edinburg and US Route 281 on State Highway 107.

Educationally, the community is served by the Edinburg Consolidated Independent School District.

[25] Previously Harwell Middle School included a portion of San Carlos.

All of Hidalgo County is in the service area of South Texas College.