Idaho Territory Pacific Northwest Unexplored Oregon Washington 1860 Mitchell mapMap of Oregon, Washington, and Part of Idaho. (Old Maps, 19th Century Maps, Americana, United States, Pacific Northwest, Washington, Oregon, Idaho, Seattle, Portland, Boise). Issued c. 1860, Philadelphia by S. Augustus Mitchell. There are many variant issues of this map, with differing borders and interior details. A comparison with other Mitchell maps of the 1860's 80's era will reveal this on close inspection. This early version shows a vast Idaho