How can I find the addresses of the Catholic Churches in the county of Mexico?

Break the churches down by diocesis.

u can try in this link
http://www.catolicos.com/diocesismexico....

Is there a particular church u are looking for?
You can check the yellow pages, I remember seeing a list with few names on it. If u can go to: www.mexicodesconocido.com.mx and once u choose ur language search for the word churches. There was an article on Porfirian churches that gives you some locations in Mexico City. Their articles and pictures are really good. Im sure you ll find something there.

What do you mean by "County of Mexico"? probably in the web page of the catholic church in Mexico.
Look here:
http://www.iglesia.org/directorio/parroq...

There are no counties in M茅xico. Probably you mean either Mexico City or Mexico State. The first one is subdivided in Delegations (Delegaciones) and the second one is subdividided in Municipalities (Municipios).
But the Churches have another kind if division, that is by parroquias.

Look here is the web page of the Conference of the Mexican "episcopado" and there is the list of diocesis in Mexico (in the whole country)
http://www.cem.org.mx/diocesis/diocesis....