640 Area Code: Trenton, New Jersey

New Jersey's 640 area code is an overlay sharing geography with the long-running 609 across central and southern coastal New Jersey. Trenton — the state capital — anchors the directory's records here. The city sits along the Delaware River at the falls that mark the head of navigation, organized around a working downtown that has reshaped itself alongside state-government employment, healthcare, and a long-running industrial history. The 640 designation, part of the North American Numbering Plan, is in the early phases of being filled with active number assignments and shares its broader footprint with the entire 609 region.

In records the directory has compiled for 640 numbers, other New Jersey cities — Cherry Hill, Edison, Elizabeth, and Jersey City — appear regularly. None of those are inside the 640 footprint. The pattern reflects standard public-record dynamics across New Jersey. The directory currently documents 3 distinct prefixes within 640 in detail, an early-stage subset that should be read as the start of working coverage rather than a comprehensive count.

Trenton's home values come in well below the US median, with median household income running well below the national figure. The city's median age sits a few years under the US reading, and population places Trenton among the smaller state-capital cities by total headcount. The 640 footprint shares those demographics with 609 because both codes serve central and southern coastal New Jersey in overlapping form, and the broader region's economic and demographic profile combines state government, the Princeton university corridor, and the Atlantic City coastal economy.