The Soil Sample Archive contains more than 226,000 samples from over 37,000 sites. Samples have metadata available in associated databases including analytical data and site and pedon data. Samples are from all 50 states and various foreign countries and were collected beginning in the 1940s. Most samples were collected by NRCS field soil scientists, and the analytical data has been used for soil classification (Soil Taxonomy) and for interpretations for soil use and management in support of the National Cooperative Soil Survey program. Typically, samples from each genetic soil horizon to a depth of approximately 2 meters are collected at representative sites.