There are 8 US Post Offices in Ontonagon County serving a total of 6,313 residents equating to 789 residents per post office. It's estimated that approximately 10,076 packages are handled across the 8 county post offices annually. Ontonagon County (/\u02cc\u0252nt\u0259\u02c8n\u0251\u02d0\u0261\u0259n/ ON-t\u0259-NAH-g\u0259n) is a county located in the Upper peninsula of the U.S. state of Michigan. As of the 2010 census, the population was 6,780, making it the third-least populous county in Michigan. The county seat is Ontonagon. The county was set off in 1843, and organized in 1848. Its territory had originally been organized as part of Chippewa and Mackinac counties. With increasing population in the area, more counties were organized. After Ontonagon was organized, it was split to create Gogebic County. The county is named after the Ontonagon River. The name is said to be derived from an Ojibwe language word Nondon-organ, meaning \"hunting river.\" A French transliteration, Nantounagon, identified the river on a 1670 French map. Alternatively, it is said to be derived from the Ojibwa onagon, which means \"dish\" or \"bowl.\" See List of Michigan county name etymologies."