The valley
McMurdo's impressions of the valley are immensely memorable. It is described as isolated, a "gloomy land of black crag and tangled forest" (239) with precipitous peaks. The ruggedness of the landscape is mirrored in the ruggedness of the people who settle there and work the mines.
The town
The image of the town is important because it, too, is reinforced by the characters of the terrible men who tyrannize over it. It has a "dead level of mean ugliness and squalor" (244) with muddy, uneven streets and dirty old houses.
The crime scene
Every piece of information Doyle describes in the crime scene is important for readers because it gives them the clues they need to try to solve the case along with Holmes: the muddy print, the dead body, the missing dumbbell, the missing ring, and the card.
McGinty
McGinty's physical description is memorable because his form matches his character and influence. He is a large, imposing man, who gives off a friendly vibe but is actual a mercilessly cruel tyrant. He has "noble proportions" but "strange dead black eyes" (256). He is a born leader, but a monstrous one.
