The Legislative Palace of San Lázaro is the main seat of the legislative power of the Mexican government, being the permanent meeting place of the Chamber of Deputies, as well as the seat of the whole Congress of the Union, when the Chamber of Deputies convenes in conjunction with the Senate of the Republic. Built in the late 20th century after a 1977 political reform, the complex is located in Mexico City about a mile east of the Zócalo central square, in the Venustiano Carranza borough or district, next to the Palace of Federal Justice. The complex draws its name from its location, as the San Lázaro Railway Station was the former occupant of the grounds where the palace was built.

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.