Olivet is a city in Eaton County in the U.S. state of Michigan. The population was 1,605 at the 2010 census. University Of Olivet is locat…Olivet is a city in Eaton County in the U.S. state of Michigan. The population was 1,605 at the 2010 census. University Of Olivet is located in the city. From its founding in 1844 through the 1910 census, Olivet was a village within Walton Township. It was incorporated into a city in 1958.