Area Code 821 – Hualahuises/Linares, NL

Overview of Area Code 821 (Mexico)

Area code 821 is a geographic National Destination Code (NDC) assigned to the northeastern region of the state of Nuevo León (NL), Mexico. It serves the municipalities of Linares and Hualahuises, along with surrounding localities. This area is part of the Sierra Madre Oriental foothills and is known for its agricultural production and historical significance. The code covers a mix of urban and semi-rural zones, with Linares being the primary commercial and administrative hub.

Geographic Coverage and Administrative Jurisdiction

The 821 area code encompasses the following key locations:

• Linares – The largest city in the region, serving as the municipal seat and economic center.
• Hualahuises – A smaller municipality located approximately 15 km south of Linares.
• Iturbide – A rural municipality to the southwest, included in the same local calling area.

Administratively, these municipalities fall under the jurisdiction of the state government of Nuevo León. The region is connected to the national highway network via Mexican Federal Highway 85, which links it to Monterrey (to the north) and Ciudad Victoria (to the south).

Dialing Formats and Caller Instructions

For callers within Mexico (domestic calls), the dialing format is:

• 01 821 XXX XX XX – When calling from another area code within Mexico.
• 821 XXX XX XX – For local calls within the 821 area code (if 10-digit dialing is used; however, in many regions of Mexico, the national prefix '01' is still required for long-distance calls).

For international callers, the format is:

• +52 821 XXX XX XX – Replace the '+' with your country's international exit code (e.g., 011 from the US/Canada).

Note that all Mexican numbers, including those in the 821 area code, have a total length of 10 digits (excluding the country code). The subscriber number is seven digits long, typically written as XXX-XX-XX.

Overlay and Numbering Considerations

As of the latest ITU-T and Mexican Federal Telecommunications Institute (IFT) updates, the 821 area code does not have an overlay. This means that the area is served exclusively by this single NDC. However, due to population growth and increased demand for telecommunication services, the IFT may introduce an overlay in the future. If an overlay is implemented, 10-digit dialing will become mandatory for all local calls, and new numbers may be assigned with a different area code while still serving the same geographic area.

Caller Instructions for Local and Foreign Callers

• Local callers (within 821): Dial the 7-digit subscriber number directly (if supported) or the full 10-digit number with the area code.
• Domestic long-distance callers (from other Mexican area codes): Dial the national long-distance prefix 01, followed by 821 and the 7-digit number.
• International callers: Dial your country's exit code (e.g., 00, 011), then Mexico's country code 52, then 821 and the 7-digit number. For example, a call from the United States to a Linares number would be: 011 52 821 123 45 67.

Always verify the current dialing procedures with your local carrier, as some mobile networks may require different prefixes for calls to landlines.