Among the best known of the Western History Collections resources is the Photographic Archives, with its holdings of over 250,000 prints and negatives. With an emphasis on the American Southwest and West for the period 1870-1940, the Photographic Archives is a major source for research and graphic illustration for many disciplines. Topically, the collection is strong on American Indians, Oklahoma's land runs and lotteries, the settlement and development of Oklahoma towns, western outlaws and lawmen, the cattle trade, agriculture, the petroleum industry, and related socioeconomic themes of the western United States. The work of individual frontier photographers such as William S. Prettyman, Andrew A. Forbes, William Soule, and W. A. Flowers are represented, along with outstanding subject-related collections such as the Walter S. Campbell and N. H. Rose Collections.