Reduce the list, select first 2 letters of the city:
Listing cities (50 place(s)). Select the City to see the postcode(s):
Listing cities (50 place(s)). Select the City to see the postcode(s):
Position: Postcodes > Mexico > Guanajuato > O.... >
Postcode finder: Mexico, List of the cities starting with O. Mexico Guanajuato Postcodes (Desktop version).