Antioquia was one of the states in the original "United States of Colombia", and is now a department in the northwest part of the Republic of Colombia.

The department has an area of 63,612 sq km (24,427 sq mi), and an estimated population of 4,500,000 (1990). It borders on the Caribbean Sea at the Gulf of Uraba, but is mostly mountainous, with two ranges of the Western Cordillera, and is bordered on the east by the Magdalena River. Medellin is the chief city.

Prior to the constitution of 1886, Antioquia and the other states were sovereign governments in their own right, and even afterwards retained some rights, such as the management of finances.

Antioquia issued its own postage stamps from 1868 to 1904. Many of the later issues, such as those from 1899, are readily available, but authentic usages on cover are scarce.