The John Riordan Three-Decker is an historic three-decker house in Worcester, Massachusetts. Built in 1888, it is a rare survivor of the earliest phase of three-decker construction in the area northwest of Worcester's downtown. It has a single story entry porch, and an atypical square projecting bay (rather than the more typical angled bay) flanking the entry. Its early occupants were lower-income white collar workers, and skilled blue collar workers, predominantly Irish in origin.[2]