Haligonian

Likely from a false folk etymology deriving Halifax from Old English hāliġ feax ("holy hair"), although it probably actually came from halh +‎ ġefeaxe ("grassy corner"). To this root halig- was added the -onian suffix, probably with analogy to other British demonyms following a similar pattern such as Oxonian, Cantabrigian, Mancunian, Glaswegian, etc. The original demonym was Halifaxian from the Nova Scotian city's founding in 1749 until the early 19th century (around the third generation of residents), when Haligonian became preferred. The reason for the change may be in part due to a negative association with the original demonym.