- Your Ad Here Montgomery County is a county located in the U.S. state of New York. As of the 2016 census, the population was 49,276. The county seat is Fonda. Sponsored Links History In 1784, following end of the American Revolutionary War, the name of Tryon County was changed to Montgomery County. It was named in honor of Richard Montgomery, an American Revolutionary War general killed in 1775 at the Battle of Quebec. |