Maycomb is an old town:
... a tired old town... nowhere to go, nothing to buy and no money to buy it with, nothing to see outside the boundaries of Maycomb County.
It is isolated from other areas due to the dishonest shenanigans of one of its founders, a tavern owner named Sinkfield. Sinkfield plied government surveyors with alcohol, a bribe that
... reduced his guests to myopic drunkenness one evening, induced them to bring forward their maps and charts, lop off a little here, add a bit there, and adjust the center of the county to meet his requirements.
The town's geographic boundaries benefited Sinkfield, but it left Maycomb isolated from the river-boat transportation of the day, and
As a result the town remained the same size for a hundred years, an island in a patchwork sea of cottonfields and timberland.
Maycomb is a town of little change with few visitors or newcomers journeying its way, and Atticus is
... related by blood or marriage to nearly every family in the town.
The close-knit population is wary of outsiders, such as Miss Caroline (who hails from dreaded Northern Alabama) and the Yankee ways of the Misses Tutti and Frutti, who not only own the "only Maycomb residence boasting a cellar," but, even worse, were also "rumored to be Republicans." The residents of Maycomb are unused to change, and modern ideas--such as those presented by the New Deal politics of President Franklin Delano Roosevelt--are disdained by most of the townspeople. Needless to say, the segregationist social policies of the Deep South are solidly entrenched in Maycomb, and free thinkers like Atticus and Miss Maudie can only be satisfied with "baby steps" when it comes to any kind of change in their town.