The municipal seat is the village of Castillo de Teayo.

[2] Of the municipality's inhabitants, 1,970 (10.52%) spoke an indigenous language, primarily Nahuatl.

The municipality of Castillo de Teayo covers a total surface area of 447.46 km².

"Teayo" comes from the Nahuatl te-ayo-k, which means "tortoise atop stone".

This is a reference to the archaeological site known as the Castle of Teayo, a syncretic blend of the Toltec, Mexica, and Huastec cultures.