John reaches what is believed to be the Hudson River in paragraph number 22 of the text;
The text reads;
"The towers are not all broken—here and there one still stands, like a great tree in a forest, and the birds nest high. But the towers themselves look blind, for the gods are gone. I saw a fishhawk, catching fish in the river. I saw a little dance of white butterflies over a great heap of broken stones and columns. I went there and looked about me—there was a carved stone with cut—letters, broken in half. I can read letters but I could not understand these. They said UBTREAS. There was also the shattered image of a man or a god. It had been made of white stone and he wore his hair tied back like a woman's. His name was ASHING, as I read on the cracked half of a stone. I thought it wise to pray to ASHING, though I do not know that god."
Although some people believe that the "city" may have been different than NYC; the following hints have caused people to believe that it is......
Ou-dis-sun is believed to be the Hudson River.
A statue with the word "ASHING" is believed to be George Washington.
A building marked "UBTREAS" is thought to be the United States Sub-Treasury building.
John walks through a building marked by stars on the ceiling and inside of its tunnels. This is assumed to be the Grand Central Terminal.