A colonia was a Roman outpost, usually established by veterans of a Roman Legion, who received land as a part of their retirement from the Legions.

Some examples would be

• Lincoln, originally Lindum Colonia.
• Colchester, originally Colonia Claudia Victricensis.
• Jerusalem (Colonia Aelia Capitolina, after the Jewish War).
• Köln originally Colonia Claudia Ara Agrippinensis.

Modern uses

In Mexico, colonia is used for a neighbourhood. It's a frequent term in Mexico D.F. addresses.

Primarily Hispanic settlements along the U.S.-Mexican border are also called colonias. These are often substandard.

Colonia is also the name of a city in Uruguay.