The Congress of the Union, formally known as the General Congress of the United Mexican States, is the legislature of the federal government of Mexico consisting of two chambers: the Senate of the Republic and the Chamber of Deputies. Its 628 members meet in Mexico City.

The Federal Government of Mexico is the national government of the United Mexican States, the central government established by its constitution to share sovereignty over the republic with the governments of the 31 individual Mexican states, and to represent such governments before international bodies such as the United Nations. The Mexican federal government has three branches: executive, legislative, and judicial and functions per the Constitution of the United Mexican States, as enacted in 1917, and as amended. The executive power is exercised by the executive branch, which is headed by the president and his Cabinet, which, together, are independent of the legislature. Legislative power is vested upon the Congress of the Union, a bicameral legislature comprising the Senate and the Chamber of Deputies. Judicial power is exercised by the judiciary, consisting of the Supreme Court of Justice of the Nation, the Council of the Federal Judiciary, and the collegiate, unitary, and district courts.