A 10-year study (2004–2013) was conducted to determine mosquito distribution and the prevalence of West Nile virus (WNV) on the Nevada National Security Site (NNSS) in south-central Nevada. Mosquito traps baited with dry ice were set overnight at sites where standing water provided potential breeding sites for mosquitoes. Captured mosquitoes were identified to species and tested for WNV. A total of 556 mosquitoes representing 6 species were captured and identified at 20 sites around the NNSS during 124 surveys. A vast majority (89%) of mosquitoes were Culex tarsalis. Two samples, both Culiseta inornata, tested positive for WNV in 2005 and 2006, both from Well 3 Pond, Yucca Flat, Nye County. Additionally, 24 birds representing 5 species were opportunistically collected and tested for WNV with no positive results. Results from this study reveal patterns of mosquito distribution across the NNSS and suggest that NNSS workers are at low risk of being exposed to WNV.