Cuicuilco is an important archaeological site located on the southern shore of Lake Texcoco in the southeastern Valley of Mexico, in what is today the borough of Tlalpan in Mexico City.

Lake Texcoco was a natural lake within the Anahuac or Valley of Mexico. Lake Texcoco is best known for an island situated on the western side of the lake where the Mexica built the city of Mēxihco Tenōchtitlan, which would later become the capital of the Aztec Empire. After the Spanish conquest, efforts to control flooding led to most of the lake being drained.