According to the 2010 census, what was the population of the city on the United States side of the Four Falls Border Crossing?
3,496
Title: Four Falls Border Crossing
Passage: The Four Falls Border Crossing is a one-way crossing between Fort Fairfield, Maine and Four Falls, New Brunswick on the Canada–US border.  Traffic is permitted to enter Canada at this location, but people entering the United States face arrest.
Title: Fort Fairfield, Maine
Passage: Fort Fairfield is a town in Aroostook County, eastern Maine, United States, located along the Canada–US border.  The population was 3,496 at the 2010 census.
Title: Hamlin - Grand Falls Border Crossing
Passage: The Hamlin - Grand Falls Border Crossing connects the towns of Hamlin, Maine and Grand Falls, New Brunswick on the Canada–US border.  The crossing is reached by Boundaryline Road on the American side and by New Brunswick Route 218 on the Canadian side.  It is the northernmost border crossing on Maine's north-south land border with New Brunswick.  In 2011, the United States replaced its border inspection facilities, which were originally built in 1964.
Fort Fairfield, Maine Four Falls Border Crossing