United Earth

United Earth was the political entity that governed the planet Earth. It was initially established in 2113 (movie Star Trek: First Contact); however, it was not until 2150 that the last nation-state, Australia, joined the government. (TNG episode "Attached")

The United Earth government is headed by a president. Lydia Littlejohn was president of United Earth at the end of the Earth-Romulan War, and during the foundation of the United Federation of Planets. (novel Starfleet: Year One)