Also a town in
upstate New York, in the
Finger Lakes region of the state.
Syracuse and
Rochester are both less than an hour away.
Waterloo, New York is most known as the "birthplace of Memorial Day". On May 5, 1866, the village had the nation's first official remembrance of those who had died in wartime. A century later, the United States Congress created a resolution officially declaring the village as the birthplace of Memorial Day. That same year (1966), Waterloo opened a Memorial Day museum.
According to the village's official website (www.waterloony.com; where most of the above information was gathered as well), Waterloo's population is 5307. Having been there before, it's similar to any of dozens of other quaint small towns in that region of New York. A nice place to take an autumn stroll through the middle of town.
A quick Yahoo search of "Waterloo" shows that there's also town/village/cities of Waterloo in the American states of Iowa, Wisconsin, Indiana, and Illinois, and also in the Canadian province of Quebec, and the Australian territory of New South Wales (and probably at least a few others, worldwide...).