Eureka is an unincorporated town and census-designated place in and the county seat of Eureka County, Nevada, United States. With a population of 414 as of the 2020 United States census, it is the second-largest community in Eureka County. Attractions include the Eureka Opera House, Raine’s Market and Wildlife Museum, the Jackson House Hotel, and t…Eureka is an unincorporated town and census-designated place in and the county seat of Eureka County, Nevada, United States. With a population of 414 as of the 2020 United States census, it is the second-largest community in Eureka County. Attractions include the Eureka Opera House, Raine’s Market and Wildlife Museum, the Jackson House Hotel, and the Eureka Sentinel Museum.