San Antonio La Isla is a municipality located in the State of Mexico in Mexico. It's municipal seat is the town of San Antonio la Isla. Its name originally was "Techialoyan" or "Tlachialoyan", which in Nahuatl means "place of those who watch". Its glyph is an eye on the apex of a pyramid that floats on water. It is located in the Matlatzinca Valley, south of Toluca, the state capital.