In To Kill a Mockingbird, the first chapter describes the town's setting in general. It is specific to the facts that there is a courthouse in the middle of the town square and stores surround it. These details can be found on pages 4-6.
In chapter 15, the town in described more vividly. It gives specific locations which include the directions of north and south. It also illustrates what the building actually look like by the way they are described:
We went by Mrs. Dubose's house, standing empty and shuttered, her camellias grown up in weeds and johnson grass. There were eight more houses to the post office corner.
The south side of the square was deserted. Giant monkey-puzzle bushes bristled on each corner, and between them an iron hitching rail glistened under the street lights. A light shone in the county toilet, otherwise that side of the courthouse was dark. A larger square of stores surrounded the courthouse square; dim lights burned from deep within them.
Atticus's office was in the courthouse when he began his law practice, but after several years of it he moved to quieter quarters in the Maycomb Bank building. When we rounded the corner of the square, we saw the car parked in front of the bank. "He's in there," said Jem.
But he wasn't. His office was reached by a long hallway. Looking down the hall, we should have seen Atticus Finch, Attorney-at-Law in small sober letters against the light from behind his door. It was dark.
Jem peered in the bank door to make sure. He turned the knob. The door was locked. "Let's go up the street. Maybe he's visitin' Mr. Underwood."
Mr. Underwood not only ran The Maycomb Tribune office, he lived in it. That is, above it. He covered the courthouse and jailhouse news simply by looking out his upstairs window. The office building was on the northwest corner of the square, and to reach it we had to pass the jail.
This description occurs the night that the mob came to haunt Tom and Atticus at the jail when the children interrupted the possible altercation.
Hope that helps!