Republic is an unincorporated community in Marquette County in the U.S. state of Michigan. It is also a census-designated place for statistical purposes and no legal status as an incorporated municipality. The CDP had a population of 470 at the 2020 census, down from 570 in 2010. The community is located mostly within Republic Township with a small p…Republic is an unincorporated community in Marquette County in the U.S. state of Michigan. It is also a census-designated place for statistical purposes and no legal status as an incorporated municipality. The CDP had a population of 470 at the 2020 census, down from 570 in 2010. The community is located mostly within Republic Township with a small portion extending north into Humboldt Township.