 All of the Republican-leaning portions of Hunterdon County and Monmouth County were taken out of the 12th district while the Democratic-leaning towns of Plainfield, Scotch Plains, Fanwood, Middlesex, Dunellen, Bound Brook, South Bound Brook, Manville, East Windsor Township, and Hightstown were added to the 12th district.Additionally, sections of Trenton, Franklin Township & Old Bridge Township
which were formerly located in the 4th and 6th Congressional districts, respectively, were also added to the 12th district.Only four counties remained