Manhattan is a grid, except for the southernmost parts - below 14th street, the roads were laid out by meandering cows. Oh, and those section in midtown where the tunnels hook into the island. Oh, and uptown, Washington Heights. Oh, and I guess a lot of Brooklyn was designed by cows too. And Queens, I guess queens is a grid, sort of, except where it isn't.

New York is a really, really, really big place. It's not "laid out" so much as "grown".