I had no idea there were cacti in Pennsylvania until I found this!
This is a picture of a Prickly Pear along the BWI Trail in Linthicum, Maryland.
Colony has been present for years, growing on a barren, shale-y road shoulder. Can't be positive that it isn't an escape from cultivation as it's in the middle of a neighborhood, but haven't seen in elsewhere in the area.
Unsure if this was planted intentionally. Will let the Masonville Cove folks weigh in!
@derekstephenhollingshead -should be the same population as https://inaturalist.ca/observations/203517535
Longest spines >3cm long, several areoles with 9 or more spines, flowers ~5cm diameter.
2 or 3 individuals, surprisingly few glochids on older pads.
Introduced?