Area code 664 in the North American Numbering Plan covers Montserrat, a tiny British Overseas Territory in the Caribbean. The 664 telephone area code, standing for "MNI," was created during a split from the original 809 area code, which was done around July 1996. A domestic call within Montserrat is seven digits. A call from another North American Numbering Plan country (such as the United States or Canada) requires 1-664- and the seven-digit phone number, in the same format as a domestic toll call.