I'm on the other side of the country, so will be there in spirit, but I think they're talking about: http://peoplesclimate.org/march/
New York City
The March - 11:30 am, Sunday, September 21st
Assembly Location: Central Park West, between 65th and 86th streets.
Enter on 65th, 72nd, 77th, 81st, or 86th street.
The march will begin at 11:30 am.
March down Central Park West and go east on 59th Street
Turn onto 6th Ave. and go south to 42nd Street
Turn right onto 42nd Street and go west to 11th Ave
Turn left on 11th Ave. and go south to 34th Street
End Location: 11th Ave. in the streets between 34th Street and 38th Street