Alger County is a county in the Upper Peninsula of the U.S. state of Michigan. As of the 2010 census, the population was 9,601. Its county seat is Munising. The Pictured Rocks National Lakeshore is located within the county.HistoryAlger County was detached from Schoolcraft County, set off and organized in 1885. The county was named for lumber baron Russell Alexander Alger, who was elected as a Michigan Governor, and U.S. Senator, and appointed as U.S. Secretary of War during the William McKinley Presidential administration. See also, List of Michigan county name etymologies, List of Michigan counties, and List of abolished U.S. counties.GeographyAccording to the U.S. Census Bureau, the county has a total area of, of which is land and (82%) is water. It is the second-largest county in Michigan by total area, mainly because of Lake Superior on the north side of the county.