The park is still 'private' with a fence around it.
This sounds like a more plausible explanation, but than most that have 
been posted.

I read a lot of irony in the song; even in the 1890's when the song was 
written the streets and sidewalks of NY were nasty - all the horses; 
playing 'London Bridge is falling' down in an Irish neighborhood.

On Feb 25, 2005, at 11:58 AM, [log in to unmask] wrote:

>
> Hello All.  After further research and asking some "old folks," I do 
> believe the "G" means Gramercy Park, because several older NYer's have 
> told me that it was still a term when they were young.    "Up in 
> G."      I was told by a 92 year old woman that "not only was the rich 
> and famous up in G, but they had fancy fences around the gardens 
> and Parks to keep the poor folks out."   Originally meaning Gramercy 
> Park and referring to the "hoytie toytie's" who became more 
> sophisticated and moved uptown to "Gramercy Park,"  it became a phrase 
> for anyone who moved "up and out of the neighborhood"  and sometimes 
> meaning "they think they're too good for us."   I am currently 
> researching and writing a book about Old Manhattan and I truly 
> appreciate this type of discussion, very colorful and thought 
> provoking.  I would appreciate any one else who would mention old 
> "sayings" "Colloquialism's" and "slang words" used exclusively in NEW 
> YORK.  Thanks.
>
Jazz is freedom. - T. Monk