Jeckyll, Thomas. Map of the United States and their Territories between the Mississippi River and the Pacific Ocean. Washington DC, 1857-8.

Thomas JeckyllMap of the United States and their Territories between the Mississippi River and the Pacific OceanWashington DC, 1857-822 1/2 x 25 inches   This impressive map of the United States west of the Mississippi River reflects the latest surveys performed along the newly established Mexican-American border by a party led by William H. Emory, an officer in the U.S. Army Corps of Topographical Engineers. Shortly after the Gadsden Purchase of 1854, Emory was assigned to lead the American boundary commission established to determine the exact line of demarcation and spent nearly two years performing the requisite surveys. The results, seen here, are among the most detailed cartographic representations of the West until after the Civil War. Delicately engraved topography and geographic features dominate much of the image, but important transportation routes, settlements, and fortifications are also named throughout. Vast swathes of unexplored territory are labeled across the Southwes