These are Common Gallinules (Gallinula chloropus). Pre-split they were called moorhens. Swamphens are something different (the only swamphen species in the US is the Gray-headed Swamphen, Porphyrio poliocephalus).
Glad to hear that they're so common! I lived in Tampa and Temple Terrace about 30 years ago and they were common around a lot of the urban stormwater detention ponds, but sadly it's not that way across most of the U.S. once you get away from the Gulf Coast.