This is probably a really stupid question, but I keep seeing the term "Mexico DF" and I can't for the life of me figure out what the DF stands for. Can someone please fill me in? Thanks.

D.istrict F.ederal

Analogous to our DC--DF and Mexico City are related in the same way as Washington and DC. Sure, there may be more than just the cities included in the terms, but people are usually referring to the cities.

DF is the abbreviation for Distrito Federal (Federal District). As mentioned above it is not a state, as The District of Columbia is not. Mexicans often call Mexico City "Mexico" or "El D.F." If you are in Mexico and someone says "I'm going to Mexico" it means Mexico City. There are also milage markers throughout the country specifically designated to show the distance to El D.F. because it is heart of the country.

Thanks everyone.