Locate a reliable Internet connection or Internet cafe in your immediate area. Use the United States Department of State website embassy and consulate-locator feature. Here you will find a list of all U.S. embassies and consulates in locations around the world including Mexico.
Locate the nearest telephone directory which may be found at the front desk of nearly any hotel, in certain public phone booths, in rail station and bus station telephone booths throughout Mexico. The directory will list all embassies and consulates located within your current location city limits. The Spanish word for consulate is "consulado," and for embassy is "embajada."
Find your local police station or ask any policeman you may find on the street or driving by. All uniformed officers will be able to direct you to the nearest American embassy or consulate without issue. The proper question to ask is "Donde esta el embajado/consulado Americano."
Flag down the first official taxi you see. Ask the driver where the American Embassy or consulate is and he or she will be able to direct you. This may be the best method of locating the site as you will find out its location and also be taken there if you wish.
Join the State Department's STEP or Smart Traveler Enrollment Program (see Resource #2). This free service allows travelers to register with the State Department prior to departure so that the agency can keep track of your progress and can better assist you should something occur. The system also keeps travelers in tune with their local embassy or consulate so that all developments are recorded.