Tehuacán is the second largest city in the Mexican state of Puebla, nestled in the Southeast Valley of Tehuacán, bordering the states of Oaxaca and Veracruz. The 2005 census reported a population of 238,229 in the city and 260,923 in its surrounding municipality of the same name, of which it serves as municipal seat. The municipality has an area of 390.36 km² (150.72 sq mi).

Originally a Native American settlement, it became officially a city in the Viceroyalty of New Spain in 1660. According to the archaeologist Richard Stockton MacNeish, the Valley of Tehuacán is the first place maize was ever cultivated by humankind. He arrived at this conclusion when he found over 10,000 teoscintle cobs in what is now known as the Cave of Coxcatlan.

In the late twentieth century, the city was well known for its mineral springs. In fact, Peñafiel (now owned by Cadbury Schweppes), a well known soft drinks manufacturer, extracts water from these wells for use in their products. Tehuacán also has an important cluster of poultry producers, making the city and its surroundings one of the most important egg producing regions in Mexico.