Niles is a city in Berrien and Cass counties in the U.S. state of Michigan, near South Bend, Indiana. In 2010, the population was 11,600 according to the 2010 census. It is the larger, by population, of the two principal cities in the Niles-Benton Harbor, Michigan Metropolitan Statistical Area, an area with 156,813 people.Niles lies on the banks of the St. Joseph River, at the site of the French Fort St. Joseph, first built in 1697 to protect the Jesuit Mission established in 1691.