El Castillo
- County:
- Starr County
- County Seat:
- No
- Area (mi²):
- 0.028
- State:
- Texas
El Castillo is a CDP located in Starr County, Texas. El Castillo has a 2025 population of 128 . El Castillo is currently declining at a rate of -3.03% annually but its population has increased by 100% since the most recent census, which recorded a population of 64 in 2020.
The median age in El Castillo is 18.8 years: 9.8 years for males, and 22.4 years for females. For every 100 females there are 116.2 males.