Lendle

The Shunned House of the title is based on an actual house in Providence, Rhode Island, built around 1763 and still standing at 135 Benefit Street; Lovecraft was familiar with the house because his aunt, Lillian Clark, lived there in 1919-20 as a companion to Mrs. H. C. Babbit.[1]
But it was another house in Elizabeth, New Jersey that actually provoked Lovecraft to write the story. As he wrote in a letter:
On the northeast corner of Bridge Street and Elizabeth Avenue is a terrible old house — a hellish place where night-black deeds must have been done in the early seventeen-hundreds — with a blackish unpainted surface, unnaturally steep roof, and an outside flight of stairs leading to the second story, suffocatingly embowered in a tangle of ivy so dense that one cannot but imagine it accursed or corpse-fed. It reminded me of the Babbit House in Benefit Street…. Later its image came up again with renewed vividness, finally causing me to write a new horror story with its scene in Providence and with the Babbit House as its basis.[2]
It is interesting to note that this location is, at least at present, the site of a plaza named in honor of Winfield Scott, who was also the namesake of Lovecraft’s own father.