The eastern portion of Wisconsin had been served by area code 414 for half a century until the Green Bay and the Fox River Valley were designated a new numbering plan area (NPA) with area code 920 in 1997, to provide more telephone numbers in the densest populated area of Milwaukee County. Although this was intended as a long-term solution, within a year 414 was again approaching exhaustion due to the continued proliferation of cell phones and pagers. The original mitigation plans called for 262 to be added as an overlay code for all of southeastern Wisconsin. However, overlays were a new concept at the time, and met with some resistance to the mixing of area codes in the same area and the ensuing requirement for ten-digit dialing. As a result, 262 was designated for a separate numbering plan area with nearly all of the territory outside Milwaukee County. A few slivers of Waukesha and Washington counties stayed in 414.
Projections in early 2019 suggested the Milwaukee suburbs would not need another area code until 2044 at the earliest, but later in 2019 no exhaust date was listed, meaning the date is 30 years or more in the future.[1]