Annotating this story is largely a matter of cross-referencing, hence these notes are kept as brief as possible. ''Passim'' is a convention denoting ''occurring too frequently in the source to practicably quote'' from the Latin adverb denoting ''here and there''.
''The Terrible Old Man'' – plays an important part in ''The Strange High House in the Mist'' (Passim.). Details pertaining to him are further elaborated there.
''Kingsport'' – this is the first reference made to the ancient town of Kingsport. There is a well-documented association between Kingsport and Marblehead, but it postdates ''The Terrible Old Man'' (written January 28th 1920, Lovecraft's first visit to Marblehead was in 17th December 1922). Thus, the name was, when devised, void of any association with Marblehead.
See, firstly, ''The Festival'' (Passim, this story was written soon after Lovecraft came a second time to ''ancient Marblehead'', before the June of 1923, though I suspect it was the Yuletide visit that inspired beautiful yet sinister Kingsport, crawling with things older and darker than Aryan men).
It is alluded to thrice in the ''Dream-Quest of Unknown Kadath'' (1. He saw slip past him the glorious lands and cities of which a fellow-dreamer of earth—a lighthouse-keeper in ancient Kingsport—had often discoursed in the old days. 2. Kuranes warns Carter that at the last he will only yearn for, amongst other sights of childhood, the tall steeples and winding hill streets of quaint Kingsport and 3. Nyarlathotep alludes to, as a part of Carter's dream-city, antediluvian Kingsport hoary with stacked chimneys and deserted quays and overhanging gables, and the marvel of high cliffs and the milky-misted ocean with tolling buoys beyond.
See also ''The Silver Key'' (with the distant spires of Kingsport on the horizon, and hints of the archaic, dream-laden sea in the farthest background and Once a gap in the trees opened up to the right, so that he saw off across leagues of twilight meadow and spied the old Congregational steeple on Central Hill in Kingsport; pink with the last flush of day, the panes of the little round windows blazing with reflected fire.), ''The Strange High House in the Mist'' (Passim), ''The Case of Charles Dexter Ward'' (the exposure of nameless rites at the strange little fishing village of Kingsport, in the Province of the Massachusetts-Bay.) and ''The Thing on the Doorstep'' (The daughter of a friend of mine had met her [Asenath Waite] before—in the Hall School at Kingsport).
''new and heterogeneous alien stock'' – the robbers are all aliens or foreigners – Ricci is an Italian, Czanek is a Slav (the name occurs in Poland, Hungary and Slovakia), and Silva almost certainly a Portuguese.
''Water Street'' – see ''The Strange High House in the Mist'' (the Terrible Old Man who talks to leaden pendulums in bottles, buys groceries with centuried Spanish gold, and keeps stone idols in the yard of his antediluvian cottage in Water Street)
''Ship Street'' – see ''The Strange High House in the Mist'' (Granny Orne, whose tiny gambrel-roofed abode in Ship Street is all covered with moss and ivy)
The brief length and ambiguous nature of the weird manifestations – as well as the spectre of the yellow-eyed man- - make this a very fine story.