Neffs is located at the junction of Pennsylvania Routes 873 and 329, approximately one mile north of Schnecksville.

The town was initially called Unionville after the Union Church that was established there in 1797.

Abraham Neff laid out the village while running a coach business and local hotel.

At that time, the first non-agricultural manufacturing plant was built in Neffs by Ted Ambrosino, who established Ambro Fashions.

The town was so concerned about the influx of additional mail and post office activity that it applied for and won a federal grant to build an upgraded modern post office facility.