Ruby Lake National Wildlife Refuge preserves nearly 40,000 acres of marshes and shallow ponds in Ruby Valley in northeastern Nevada. Established in 1938, it occupies the bed of an ancient lake and now forms a spring-fed wetland oasis in the arid Great Basin. Stretching about 16 miles long and up to 3 miles wide, the refuge supports hundreds of species of native and migratory birds and mammals. Ruby Marsh is especially important as a nesting area for greater sandhill cranes and trumpeter swans. Its ecological significance was further recognized in 1972 when Ruby Marsh was named a National Natural Landmark.