Bar Harbor is a resort town on Mount Desert Island in Hancock County, Maine, United States. As of the 2020 census, its population is 5,089. The town is home to the College of the Atlantic, Jackson Laboratory, and MDI Biological Laboratory. During the summer and fall seasons, it is a popular tourist destination. Bar Harbor is also home to the largest parts of Acadia National Park, including Cadillac Mountain, the highest point within 25 miles of the coastline of the eastern United States.