Princeton is an unincorporated census-designated place in Latah County, Idaho, United States. Princeton is located on Idaho State Highway 6 3 miles east-southeast of Potlatch. Princeton has a post office with ZIP code 83857. As of the 2010 census, its population was 148.A post office called Princeton has been in operation since 1894. The community was named after Princeton, Minnesota, the native home of an early settler.