Eureka is an unincorporated township in and the county seat of Eureka County, Nevada, United States. Eureka is by far the largest community in Eureka County. Attractions include the Eureka Opera House (built in 1880 and restored in 1993), Raine's Market and Wildlife Museum (built 1887), the Jackson House Hotel (built 1877), and the Eureka Sentinel Museum (housed in the 1879 Eureka Sentinel Newspaper Building).
Eureka is part of the Elko Micropolitan Statistical Area.
Eureka is located at 39°30′42″N 115°57′42″W / 39.51159°N 115.961723°W / 39.51159; -115.961723, in the southern part of Eureka County, at 6,481 feet (1,900 m) in the Diamond Mountains, in a draw on the southern end of Diamond Valley, between Antelope and Newark valleys. The total population of Eureka and the surrounding area (census tract 1 — Eureka CCD) is 1,103.