443 area code code#
It was now obvious that a second area code was necessary. Plans had already been underway to break this longstanding scheme, but it soon became apparent that this would not free up enough numbers to keep up with demand. For over 40 years, it was possible to make a call between portions of the Washington area with only seven digits, since every number in 301 and northern Virginia's 703 was given a "hidden" number in the District's area code 202. The supply of available numbers was further limited by the fact that most of the Maryland side of the Washington area shares an LATA with northern Virginia and the District itself.
However, by the late 1980s, 301 was on the verge of exhaustion due to the rapid growth of fax machine usage and the Baltimore and Washington suburbs. This made Maryland one of the most-populous states to be served by a single area code. Before these area codes were created, all of Maryland had been served by 301 since the institution of area codes in 1947, even though the state is home to two very large metropolitan areas-Baltimore and the Maryland suburbs of Washington, D.C.