Armonk
Market InsightsArmonk is a hamlet and census-designated place in the town of North Castle, New York located in Westchester County. As of the 2010 census, Armonk's CDP population is 4,330 and it has a total area of 6.1 square miles, of which 6.0 square miles is land and 0.077 square miles, or 1.54Â percent, is water. Armonk is well known as being the headquarters of IBM.