THE FINCH HOUSE. Atticus's house is described from time-to-time by Scout. You can find references to various parts of the house in Chapters 3, 6, 8, 10, 11, 12, 13, 14, 15, 16, 22, 23, 24, 27, 28, 29 and 30.
THE RADLEY PLACE. The Radley House is mentioned often in the first six chapters, with a particularly good description in Chapter 1. Additional information is found in Chapters 4, 5 and 6.
MISS RACHEL'S HOUSE (DILL'S). I don't believe the author provides much of a description of Dill's Aunt Rachel's house other than the mention of her fishpool and the "low wall that separated Miss Rachel's yard from our driveway" in Chapter 6.
MISS MAUDIE'S HOUSE. Miss Maudie's house is best described in Chapter 5; and in Chapter 8, which describes the fire that destroys it.
THE SCHOOL. The descriptions of Maycomb's elementary and high schools are very limited, with some mention in Chapters 2 and 3; and of the auditorium in Chapter 28.
THE POST OFFICE. I don't believe there is any description whatsoever of the post office, though it is mentioned in Chapters 4 and 15.
I'm sorry that I misread your request for house "locations" for descriptions of the houses. Check out the excellent eNotes Map of Maycomb at the links below: