Tlacotalpan is a city in Tlacotalpan Municipality in the Mexican state of Veracruz, declared a World Heritage Site by UNESCO in 1998 primarily for its architecture and colonial-era layout. The town was established in 1550 on what was originally an island in the Papaloapan River. From the colonial era to the 20th century, it was an important port, one of few interior river ports in Latin America. However, with the construction of the railroad, Tlacotalpan's importance faded.