El Oro de Hidalgo is a municipality located in the State of Mexico within the United Mexican States. It serves as one of 125 municipalities in the state, with the town of El Oro de Hidalgo serving as its municipal seat.
The name "El Oro" translates to "the gold" in Spanish. The municipality is also associated with the alternative Nahuatl name "Teocuitlatl," which means "sacred excrement." The official seal of the area features an Aztec glyph that incorporates symbols representing both gold and caves, reflecting the many caves found within the municipality.