The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel. The peninsula lies east of the Isthmus of Tehuantepec, a northwestern geographic partition separating the region of Central America from the rest of North America.

The peninsula comprises the Mexican states of Yucatán, Campeche, and Quintana Roo; the northern part of the nation of Belize; and Guatemala's northern El Petén Department.

The proper derivation of the word Yucatán is widely debated. Hernan Cortes, in the first of his letters to Charles V, the Holy Roman Emperor, claimed that the name Yucatán comes from a misunderstanding. In this telling, the first Spanish explorers asked what the area was called, and the response they received, "Yucatan," was a Yucatec Maya word meaning "I don't understand what you're saying." Others claim that the source of the name is the Nahuatl (Aztec) word Yokatlān, "place of richness."

The Yucatán Peninsula comprises a significant proportion of the ancient Maya Lowlands (although the Maya culture extended south of the Yucatán Peninsula, through present Guatemala and into Honduras and highland Chiapas). There are many Maya archaeological sites throughout the peninsula; some of the better-known are Chichen Itza, Tulum and Uxmal.Indigenous Maya and Mestizos of partial Maya descent make up a sizable portion of the region's population, and Mayan languages are widely spoken there.

Yucatán (Spanish pronunciation: [ʝukaˈtan]), officially the Free and Sovereign State of Yucatán (Spanish: Estado Libre y Soberano de Yucatán), is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 106 municipalities, and its capital city is Mérida.

It is located in Southeastern Mexico, on the north part of the Yucatán Peninsula. It is bordered by the states of Campeche to the southwest, Quintana Roo to the northeast and the Gulf of Mexico lies off its north coast.

Before the arrival of Spaniards to the Yucatán Peninsula, the name of this region was el Mayab. In Mayan language, "ma' ya'ab" is translated as "a few". It was a very important region for the Mayan civilization, which reached the peak of its development on this place, where they founded the cities of Chichen Itza, Izamal, Motul, Mayapan, Ek' Balam and Ichcaanzihóo (also called T'Hó), now Mérida.

After the Spanish conquest, Yucatán Peninsula was a single administrative and political entity, the Captaincy General of Yucatán. Following independence and the breakup of the Mexican Empire in 1823, the first Republic of Yucatán was proclaimed which then was voluntarily annexed to the Federal Republic of United Mexican States on December 21, 1823. Later on March 16, 1841, as result of cultural and political conflicts around the federal pact, Yucatán declared independence from Mexico to form a second Republic of Yucatán, but eventually on July 14, 1848, Yucatán was definitely rejoined to Mexico. In 1858, in the middle of the caste war, the state of Yucatan was divided for the first time, establishing Campeche as separate state (officially in 1863). During the Porfiriato, in 1902, the state of Yucatan was divided again to form the Federal territory that later became the present state of Quintana Roo.