Upper Saddle River was originally settled by the Lenape Native Americans and was colonized in the 18th century principally by Dutch settlers who built mills along the Saddle River. The area was granted borough status in 1894 and remained principally rural until the 1950s. The suburban growth of New Jersey affected Upper Saddle River and surrounding municipalities, as the borough's population increased tenfold from 1950 to 1970. The population has remained fairly constant since 1970.