The history of the Yucatán Peninsula is deeply intertwined with its unique geology and ecology. From the ancient Maya to modern-day tourism, the land and its resources have shaped the course of Yucatecan events. And the Yucatán, in turn, has helped shape the course of Mexican history, from being the stage upon which the early Spanish conquest was conducted to helping rescue a moribund Mexican economy in the 1980s. An understanding of the Yucatán Peninsula’s land, ecology, culture, and politics is vital to understanding the region today.

The Yucatán Peninsula spans some 113,000 square kilometers (70,215 square miles) in southeastern Mexico, and is made up of three states: Yucatán, Campeche, and Quintana Roo. It has more than 1,600 kilometers (994 miles) of shoreline, with the Caribbean Sea to the east and the Gulf of Mexico to the north and west. To the southwest are the Mexican states of Tabasco and Chiapas, and directly south are the countries of Belize and Guatemala.

Geologically, the Yucatán Peninsula is a flat shelf of limestone, a porous rock that acts like a huge sponge. Rainfall is absorbed into the ground and delivered to natural stone-lined sinks and underground rivers. The result is that the Yucatán has virtually no surface water, neither rivers nor lakes. (It also has very few hills.) The geology changes as you move south, and the first sizable river—the Río Hondo—forms a natural boundary between Belize and Mexico.