I [George M. Wheeler] have the honor to submit the following report for the fiscal year ending June 30, 1877: Including the expeditions of 1876-'77, the fields occupied will have embraced parts of the States and Territories of California, Oregon, Nevada, Texas, Arizona, Colorado, Idaho, Montana, New Mexico, Utah, and Wyoming. The remaining political divisions of the area west of the one-hundredth meridian, into which parties of this expedition have not entered for its survey, are the State of Kansas and the Territories of Washington and Dakota. The work so far has been directed to the most rugged and thinly-settled portions of the western mountain region. As time and means permit, the areas occupied will adjoin the sections of territory already entered and continue toward completion the topographical survey of the entire region.