This report was most important for the opening of travel and settlement in West Texas and New Mexico. By these explorations a supply and potential railroad route was surveyed across West Texas, and this became the main passageway for soldiers, settlers and gold seekers. The surveyors were pleased with what they saw, pointing out the large population which could be supported in the Rio Grande Valley, as well as the strategic importance of El Paso. The Simpson report is one of the first thorough surveys in New Mexico. Related to it are the many handsome plates, as well as one of the maps. The other map shows the routes across Texas. The plates with the Simpson report make it an important American color plate book.