The Republic of Yucatán () was a sovereign state during two periods of the nineteenth century. The first Republic of Yucatán, founded May 29, 1823, willingly joined the Mexican federation as the Federated Republic of Yucatán on December 23, 1823, less than seven months later. The second Republic of Yucatán began in 1841, with its declaration of independence from the Centralist Republic of Mexico. It remained independent for seven years, after which it rejoined the United Mexican States. The area of the former republic includes the modern Mexican states of Yucatán, Campeche and Quintana Roo. The Republic of Yucatán usually refers to the Second Republic (1841–1848).