Many passages describing the setting of Maycomb can be found in the opening chapter of Harper Lee's To Kill a Mockingbird. One of the first things we learn is that, when Scout and Jem are younger, there are two houses on their street that they refuse to approach, and these houses are considered their "summertime boundaries." The first house belongs to the old and cantankerous woman named Mrs. Dubose and is two doors to the north of the Finches; the second belongs to the Radleys and is three doors to the south of the Finches, as we see in the following passage:
[O]ur summertime boundaries ... were Mrs. Henry Lafayette Dubose's house two doors to the north of us, and the Radley Place three doors to the south. (Ch. 1)
Later in this same chapter, we learn that the Radley Place stands on a "sharp curve beyond" the Finches house so that, walking south, "one faced its porch." Also, based on information in this same chapter, we can deduce that Dill's aunt, Miss Rachel Haverford, is the Finches' immediate northerly next-door neighbor. We know this is the case because, the morning Scout and Jem meet Dill, they are playing in their back yard when they hear a noise. They rush over to the "wire fence" separating Miss Rachel's yard from their own, expecting to see new puppies but instead find Dill.
Chapter 2 also provides some revelatory information describing the layout of the Finches' neighborhood. Of particular importance, we learn that Scout's first-grade teacher, Miss Caroline, lives with Miss Maudie as her boarder:
She boarded across the street one door down from us in Miss Maudie Atkinson's upstairs front room. (Ch. 2)
This tells us that Miss Maudie, a close friend of the Finches, lives diagonally across the street from the Finches.
The moment of the fire in Chapter 8 reveals further information about the layout of the Finches' neighborhood in Maycomb. Scout describes in her narration that "smoke was rolling off our house and Miss Rachel's house like fog off a riverbank" (Ch. 8). This is because Miss Rachel, who is the Finches' northerly next-door neighbor, lives right across the street from Miss Maudie, whose house is on fire. Scout further relays that "[a]nother fire truck appeared and stopped in front of Miss Stephanie Crawford's." This is because Miss Stephanie lives directly next door to Miss Maudie and directly across the street from the Finches, making Miss Stephanie the southerly next-door neighbor of Miss Maudie. Earlier, in Chapter 6, we learn that "Mr. Avery boarded across the street from Mrs. Henry Lafayette Dubose's house." If Mrs. Dubose lives two doors to the north of the Finches, immediately next door to Miss Rachel who lives across from Miss Maudie, then we know Mr. Avery is Miss Maudie's second next-door neighbor, her northerly neighbor.
Other information about the neighborhood, such as where the school is located, where Cecil Jacobs lives, and where the post office and town square are located, can be found in chapters 2, 4, and 15.