Imperial County was founded on August 7, 1907 and was originally part of San Diego County. Its county seat is in El Centro. The area was visited as early as 1540 by Hernando de Alarcon, discoverer of the Colorado River. While the area was explored by Spanish explorers and Catholic friars and settlements did exist along the Butterfield Stage Route as early as 1858, true development did not take hold until water was brought into the area in 1901.