Penn is an English surname from the Old English penn, "enclosure" or "sheepfold", or from the Celtic pen, "hill", as in many Welsh place names. William Penn, the Quaker who founded Pennsylvania, gives the name its strong American resonance. Penn is a quiet choice: it peaked at number 1,869 in 2014, has moved between number 2,000 and 3,000 since and ranks number 2,706 in 2025, with 48 births.