The municipality of San Agustín Tlaxiaca is one of the eighty-four municipalities that make up the state of Hidalgo, Mexico. Whose municipal seat is the town of San Agustín Tlaxiaca. The municipality is located to the south center of the Hidalgo territory between the parallels 19°57 'and 20°12' of north latitude. Meridians 98°46 'and 99°05' west longitude. With an altitude between 2100 and 3000 meters above sea level, this municipality has an area of 297.2 km2, and represents 1.43% of the state's surface, within the geographical region known as Valle del Mezquital. It borders to the north with the municipalities of Ajacuba, Actopan, El Arenal and Mineral del Chico.
To the east with the municipalities of Mineral del Chico, Pachuca de Soto and Zapotlán de Juárez. To the south with the municipalities of Zapotlán de Juárez, Tolcayuca and with the state of Mexico. To the west with the state of Mexico and the municipality of Ajacuba. San Agustín Tlaxiaca is considered within the metropolitan municipalities of the metropolitan area of Pachuca, also integrated by the municipalities of Epazoyucan Pachuca de Soto, Mineral del Monte, Mineral de la Reforma, Zapotlán de Juárez and Zempoala, being Pachuca de Soto the central municipality.