According to the 2000 Census, its population is 26705, in 8.96 square miles of land area, for a population density of 2980 people per square mile. It's located at latitude 43N, longitude 76W.
Since it's very near the US/Canada border, it is a popular shopping spot for some Canadians. "Meet in Watertown" is apparantly an old expression, and this is the Watertown it refers to.