Gulf of Mexico numerous bays and smaller inlets. A number of rivers empty into the gulf, most notably the Mississippi River and Rio Grande in the northern gulf, and the Grijalva and Usumacinta rivers in the southern gulf. The land that forms the gulf's coast, including many long, narrow barrier islands, is almost uniformly low-lying and is characterized by marshes and swamps as well as stretches of sandy beach. The Gulf of Mexico is an excellent example of a passive margin. The continental shelf is quite wide at most points along the coast, most notably at the Florida and Yucatán Peninsulas. The shelf
Name of Mexico to the formation of the Mexican Republic which formally is known as the United Mexican States. Complications arose with the capital's former colloquial and semi-official name "Ciudad de Mexico, Distrito Federal (Mexico, D.F.)", which appears on postal addresses and is frequently cited in the media, thus creating a duplication whereas the shortened name was "Mexico, D.F., Mexico". Legally, the name was Distrito Federal (Federal District or District of the Federation). This ended with the change in statute of Mexico City into a state in 2016. Today it is officially called "Ciudad de México, México" abbreviated CDMX, Mexico. The official name