I [George M. Wheeler] have the honor to submit the following report for the fiscal year ending June 30, 1878: At the close of the present field season parties of the survey will have been engaged in fourteen of the fifteen States and Territories, a part or all of which lie west of the 100th meridian of longitude; the remaining political division (Dakota) alone having been unvisited. The progress of the work since its commencement has been directed over connected areas, and in such manner that, at a minimum of time and expense, as large areas as practicable, pursuant to required methods, shall be topographically surveyed in detail, to the end that the War Department shall have, at as early a date as possible, a complete map of the entire region.