Where is the "Bottom" located in "Sula" and what is the symbolism behind its name?

Sula by Toni Morrison is a novel set in the town of Medallion, Ohio. Bottom is an area of town up in the hills where the town’s black residents live. White people live down in the valley, closer to the river. There are both practical and symbolic implications of the location of Bottom.

In practical terms, land in a valley, near the river, is more valuable because it is richer farm land. As a river flows through a valley, it irrigates the land and deposits nutrients that make it desirable for growing crops. As it is the more desirable land to own and farm, it is owned by the white residents, who have more money and power. Bottom, located up on the hill, is not valuable as farm land and because it is cheaper land, it becomes the home of the town’s poor black residents.

By the time the book begins, Bottom has become a suburb. The trees and buildings of Bottom are being torn down to make room for a golf course, a symbol of white wealth. The story of the founding of Bottom is also symbolic of the power white people have over black people in Medallion. Bottom got its name from a farmer who promised “bottom land” and freedom to his slaves in exchange for some particularly hard work. While the slaves took that to mean land down at the bottom of the valley, something of value, the farmer tricked them by naming the undesirable area up in the hills “Bottom,” thereby tricking them into wanting it. This story is told as a joke by both black and white residents but it is symbolic of the power relationships that exist among the black and white communities in Medallion, Ohio.

The "Bottom" is part of the town of Medallion, Ohio, situated in the hills above the town "and spread all the way to the river."

The story of how the Bottom came into being is recounted in the opening chapter of the novel, although the veracity of the story is somewhat dubious as it is introduced in the context of a joke.

A farmer promises freedom and land to a slave if the slave agrees to do some difficult work. The slave completes the tasks and the farmer equivocates, playing on a misuse of language to suggest that the only land he can give the slave is "valley land" up in the hills.

When the slave asks for an explanation as to how valley land could be situated up in the hills, the farmer replies with a roundabout and creative lie.

"'High up from us,' said the master, 'but when God looks down, it's the bottom. That's why we call it so. It's the bottom of heaven—the best land there is.'"

This is the tale of the Bottom's origin, and it expresses the full and symbolic meaning of the term. The Bottom is a social status that we can associate with the physical meagerness of the land and its value as farm land. The name of the town, then, is a statement on the marginal status of the people who live there.

With these various meanings to the name (the bottom of heaven, the location in the hills and the social meaning), the name of the town becomes endowed with irony. This irony is reinforced when, late in the novel, the wealthy residents of Medallion take over the Bottom, replacing the poorest residents of the town with the "top" residents in terms of privilege.

Thus the privileged view from the hills enjoyed by the people of the Bottom was not entirely ironic, though it is ultimately taken from them by the same group that swindled them with it in the first place.

In Sula, how was the neighborhood established and how is "The Bottom" symbolic?

In Toni Morrison's Sula, the neighborhood known as "The Bottom" is ironically the hilly land in the area of town.  The white residents claimed the more hospitable valley surrounding The Bottom.  They tell the black residents that The Bottom is closer to the sky and therefore closer to God and Heaven.  The name of the town is supposed to be symbolic of the bottom of Heaven; however, the town is really more like the bottom of the socioeconomic hierarchy as most people in the area are poor.  So the name of the town suggests ironic twists within the context of the novel.