Harper Lee also makes it clear that a person living in Maycomb but coming from somewhere else is not the only type of outsider in the town. People who are different also qualify. Dolphus Raymond comes from an old and wealthy family, but there is no bigger outsider in all of Maycomb. His decision to live with a black mistress immediately casts him as an outsider--with or without his weaving walk and bottle in a paper sack. Boo Radley is also an outsider; because of his perceived mental instability and since he is never seen, people consider him an outcast even in his own neighborhood. Uncle Jack is also an outsider; he has moved away from the county of his roots, gotten an education, and works in a big city in the North. The Misses Tutti and Frutti are outsiders because of their disability. The Ewells are outsiders because of their bottomless social status.
Other characters fit a more traditional definition of an outsider. The prosecutor, Mr. Gilmer, comes from a neighboring county. Miss Caroline comes from North Alabama--akin to being born north of the Mason-Dixon Line. Aunt Alexandra, on the other hand, is new to the town of Maycomb, but because of her family history--and because she fits in so perfectly--she is not considered an outsider.
The idea of an "outsider" is not hard to develop in a small town; it seems to be human nature to be suspicious of those who haven't been around for awhile. In To Kill a Mockingbird, Lee begins the novel with some exposition about the townspeople of Maycomb, including the Haverfords, "in Maycomb County a name synonymous with jackass", and Scout's ill-fated attempt to explain to her teacher, who is new in town, the reason Walter Cunningham doesn't have any lunch:
"Walter's one of the Cunninghams, Miss Caroline. . . .They never took nothing off of nobody, they get along on what they have. They don't have much, but they get along on it."
These kind of descriptions, found throughout the novel, reinforce the idea that in a small town, everyone knows everyone, causing the arrival of an outsider to register suspicion; an outsider doesn't fit into any pre-determined categories, and is therefore someone to be feared.