Hunterdon County is a county located in the western section of the U.S. state of New Jersey. At the 2020 census, the county was the state's 18th-most populous county, with a population of 128,947, its highest decennial count ever and an increase of 598 (+0.5%) from the 2010 census count of 128,349, which in turn reflected an increase of 6,360 (5.2%) from the 121,989 counted in the 2000 census. Its county seat is Flemington. The county is part of the Central Jersey region of the state.

Burlington County is a county in the South Jersey region of the U.S. state of New Jersey. The county is the largest by land area in New Jersey and ranks second behind neighboring Ocean County in total area. Its county seat is Mount Holly. As of the 2020 census, the county was the state's 11th-most-populous county, with a population of 461,860, its highest decennial count ever and an increase of 13,126 (+2.9%) from the 448,734 recorded at the 2010 census, which in turn had reflected an increase of 25,340 (6.0%) from the 423,394 enumerated at the 2000 census. The most populous place in the county was Evesham Township with 46,826 residents as of the 2020 census. Washington Township covered 102.71 square miles (266.0 km2), the largest area of any municipality in the county. The county is part of the South Jersey region of the state.