According to North American Numbering Plan, 603423 located in MERRIMACK, New Hampshire. the first three digits 603 locate to state New Hampshire, 423 locate the city MERRIMACK, furthermore, we also provide some other information such as the zip code example(s) 03054, carrier NO NEW ENGLAND TEL OP DBA FAIR, and the latitude and longitude is 42.8589 -71.4907. Please pay attention that the detail we provide only as a reference, the details of the zip code may be not complete, the latitude and longitude likely to have deviation.

Here are some random corresponding phone numbers.