Elko County Nevada Map shows the county’s location, the county seat, neighbouring counties, the state capital, etc. Elko County is located in the northeastern part of Nevada. Its total area is 17,203 sq mi (44,560 sq km), where 17,170 sq mi (44,500 sq km) land area and 33 sq mi (90 sq km) is water area. Elko is the county seat and also the largest city.