Green’s Dictionary of Slang

up top n.

1. (Aus.) northern Australia; also as adv.; thus uptoppers, those who live there.

R. Dorien Venturing to Aus. 181: The occupants liked living ‘up top’, would not live anywhere else.
J. Dingwell One String 100: First time in Australian history that Up Top has had these experiences. [Ibid.] 109: Up Toppers called the freshwater Johnstone crocodile an alligator.
H.C. Baker I was Listening 127: Months of enforced idleness in remote places [...] ‘Up top’ he had been a member of a gang [AND].

2. (N.Z. prison) a prison’s main buildings.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 196/2: up top n. 1 a prison’s main buildings, usually incorporating the offices of the administrative staff and the highest security wings.

3. (US black) New York City, from perspective of the South.

[US]Pelecanos (con. 1972) What It Was 12: He been goin up top [...] coppin at that spot in Harlem.
[US]‘Dutch’ ? (Pronounced Que) [ebook] When it came to weight, he couldn’t fuck with the prices the New York crews were giving. What they were pushing them for in VA, he was paying for up top!

4. in attrib. use of sense 2, pertaining to New York City.

[US]‘Dutch’ ? (Pronounced Que) [ebook] Norfolk seemed to be infested with up-top crews, big and small. For that reason, he had the biggest beef with up-top cats.

5. (US prison) a prison in the north of New York State as seen from New York City.

[US]Rayman & Blau Riker’s 396: For those going ‘up top,’ or to state prison, there’s a bus standing by.