Historically, it is one of a few crossing points across a marsh stretching 25 miles (40km) from Lough Neagh to Carlingford Lough, following the course of a prehistoric glacial overflow channel from which it derives the second half of its name. The first half derives from Colonel Charles Poyntz.
The pass which gave name to the town is on a major route southwards and was named after Lieutenant Charles Poyntz from Gloucestershire who defended it against Hugh O'Neill, 3rd Earl of Tyrone in 1598.