From her 2018 book “Corktown: The History of a Toronto Neighbourhood and the People Who Made It“, Coralina R. Lemos (historian, author and heritage advocate) wrote about the origin of Trefann St:
“When John Hugh Roberts came to Canada he settled in Toronto with his wife, Ann, and their children, working as a tailor as he had done in his native Wales. Located east of Parliament Street, Trefann was initially a narrow road that ran north from Queen Street. At its northernmost exit, the road took a westerly bend and connected to Robert’s Place; ending near John Roberts’ residence on Sydenham Street (now Shuter Street). The name, which is of Welsh origin, came about as part of Mr. Roberts’ lot purchase on either side of this street and written similar to the county borough of Torfaen, where the town of Pontypool is recorded as his birthplace.
Considering that early land records note this street as “Tref-Ann,” it may be an indication that Mr. Roberts wanted to grace this road using his wife’s name while adding his own to Robert’s Place farther north. Although historically the word ‘Tref‘ in Welsh has a few different definitions, its origin is associated with property.”