While the setting of a novel may encompass an overall area, there are also specific settings for each chapter or circumstance.
Chapter 5 of The Graveyard Book is initially set in the Owenses' tomb in the graveyard, at the top of the hill in Old Town. Neil Gaiman's graveyard is based on an actual English graveyard, the Highgate Cemetery West.
You can see Highgate's influence in Chapters 6 and 7 of the novel. Here's a website which describes a little more about Gaiman's graveyard.
In the beginning of Chapter 5, Bod knows that something is in the air. There is a general air of excitement, his mother is cleaning, and everyone else seems preoccupied. Bod knows that all the excitement is based on an event called the Macabray. He visits the Bartleby mausoleum, but no one there has any time for him. In search of some answers, Bod visits Liza Hempstock at Potter's Field (another setting in this chapter), but sees no one there. His guardian, Silas, tells him the Macabray is a dance of some sort, and the only ones who can dance the Macabray are either dead or alive. Silas states that he is neither, and therefore, cannot participate in the dance.
Bod eventually smells a strange, sweet scent in the air, and finds the origin of this scent at the Egyptian Walk. This setting is still located in the graveyard. Egyptian Walk is where Bod spies the lady Mayor, Mrs. Caraway, and three men cutting white blossoms from the bushes and filling baskets with the blooms. Apparently, this is the first time the winter flowers have bloomed in eighty years.
Eventually, Bod leaves the graveyard and makes his way down to the municipal gardens in front of Old Town Hall. There, he sees many people walking around the gardens, all wearing white blossoms pinned to their clothes. When midnight dawns, he sees the dead from the cemetery walking down the hill. The dead mingle with the living, and all dance the Macabray in the town square.
At last, when all is over, Bod returns to the Owenses' tomb. The next day, he walks up to where the black obelisk and the amphitheater at Josiah Worthington's tomb are; both are situated at the top of a hill in the graveyard, overlooking the city of Old Town. There, he questions Josiah Worthington about the dance on the previous night, but Josiah tells him that no one ever discusses the dance.
As you can see, there are quite a few settings in Chapter 5, but the main settings are in the graveyard and the square in Old Town.