Ferguson County was bounded by the Simcoe Mountains on the south, the Cascade Mountains on the west, Walla Walla and Stevens counties on the east, and the Wenatchee River on the north.
Of the several officials appointed by the Territorial Legislature to administer the county, including James H. Wilbur, Alfred Hall, and W. Shaugh, only one, Fielding Mortimer Thorp (1822-1894), was an actual settler in the region. W. D. Lyman’s History of the Yakima Valley Washington explains:
“At the time there were not a hundred people living in the whole vast area, and they felt no need of the encumbrance of a county government. Hence the appointees never qualified and Ferguson ... died 'a-bornin' ” (Vol., 1, p. 284).
A. J. Splawn, an early resident in the Kittitas and Yakima valleys and an important historian of the region, expands on this in Ka-mi-akin: The Last Hero Of The Yakimas:
“The settlers did not need it. They had protected themselves up to this time and felt they were abundantly able to do so for a number of years to come. What money they got from time to time they very much needed for their own support, and did not feel like being taxed for the upkeep of a bunch of office holders over at Olympia” (p. 159).
The county was named in honor of James Leo Ferguson, a member of the house from Skamania County. After examining the House Journal, historian/librarian Charles W. Smith surmised the reason Ferguson was thus honored in a 1909 article (reprinted in 1913) documenting the naming of Washington's counties:
"On December 20, 1862, shortly after the opening of the legislature that created Ferguson county, a resolution was passed by the house to expunge from the journal all that portion which related to a contest over the seat of James L. Ferguson. It would appear that a 'scurrilous' attack had been made by one Justin Chenoweth, upon Mr. Ferguson and other members of the house. It may have been invindication of Mr. Ferguson that his friends sought to associate his name with the county created during the session while the return to Yakima may indicate the work of Mr. Ferguson's enemies, or may else be attributed to the wishes of the residents of the county" ("The Naming of Counties...").
An Illustrated History of Klickitat, Yakima and Kittitas Counties, With An Outline Of The Early History of The State Of Washington, published in 1904, explains:
“The appointees were so little elated over the honors bestowed upon them that they never performed their respective duties, probably never qualified, and, in brief, the county gained no existence except on the statute book” (p. 156).The act establishing Ferguson County was repealed on January 18, 1865.
On January 21, 1865, the area that had been Ferguson County became Yakima County, with the exception that the eastern border of the county became the Columbia River from below Wallula to Wenatchee. In 1883 Kittitas County was carved out of Yakima County.