MCC (Mobile Country Code) — Definition

The MCC, or Mobile Country Code, is a three-digit number that identifies the country a mobile network belongs to.

The United States uses 310 through 316, the UK uses 234 and 235, India uses 404 and 405, and so on. It's the first part of the unique fingerprint that identifies any carrier in the world.

In practice

You'll see the MCC sitting next to the MNC in your phone's APN settings. Your phone usually fills it in automatically from the SIM, so you rarely change it by hand. Paired with the MNC, it pinpoints exactly which carrier a SIM belongs to.