In Mexico, the neighborhoods of large metropolitan areas are known as colonias. One theory suggests that the name, which literally means colony, arose in the late 19th and early 20th centuries, when one of the first urban developments outside Mexico City's core was built by a French immigrant colony. Unlike neighborhoods in the United States, colonias in Mexico City have a specific name which is used in all official documents and postal addresses. Usually, colonias are assigned a specific postal code; nonetheless, in recent urban developments, gated communities are also defined as colonias, yet they share the postal code with adjacent neighborhoods. When writing a postal address the name of the colonia must be specified followed by the postal code and preceding the name of the city. For example:

Calle Insurgentes 145

Colonia Condesa

Del. Cuauhtémoc

06767 México, D.F.