Buffalo, New York
Buffalo, New York, is the closest major U.S. city to Toronto.
It can be reached by taking the Queen Elizabeth Way out of the city all the way to the U.S. border and crossing one of the three bridges along the Niagara River.
From the U.S. side of the border, Buffalo is a short drive south from Niagara Falls, New York.
They have just started a city wiki dubbed BufWiki.