Nataqua Territory was an unrecognized provisional United States territory in northeast California and western Nevada from 1856 to 1861. At the time the location of the eastern boundary of California and the western boundary of Utah were still vague. Utah in 1849 had claimed land as far as the crest of the Sierra Nevada. Utah erected Carson County in 1854, organized it in 1855, and sent 60 Mormon families in the spring of 1856 to colonize the east slope of the Sierra Nevada. Non-Mormon residents on the east slope felt physically cut off from California, and alarmed at the prospect of coming under political control of Salt Lake City.
Twenty residents of Susanville in Honey Lake Valley (now in Lassen County, California) on the east slope of the Sierra Nevada apparently did not feel they were part of California, and did not care to be part of Utah. Led by Peter Lassen and Isaac Roop, they met in "mass convention" 26 April 1856 at Roop's house. Their main purpose was to draw up rules for, and promote their valley. In the process the convention wrote, "Inasmuch as Honey Lake Valley is not within the limits of California, the same is declared a new territory . . . the said territory to be named Nataqua . . ." They went on to define a rectangle shaped territory by latitude and longitude which technically did not include their own valley, but did encompass most of what soon became western Nevada. About 600 residents of future Nevada were apparently unaware of the Honey Lake Valley "convention."
In the summer of 1857 most east slope Mormons hurried off to defend Salt Lake City from an invasion by the U.S. Army. The time was ripe for the remnant non-Mormon residents of the east slope to increase their efforts to exert independence from both California and Utah. A new convention on 8 August 1857 in Genoa (formerly Mormon Station) petitioned Congress for the creation of the Nevada Territory, and absorbed the Nataqua movement by making it a county in the proposed territory. On 3 October 1857 the Honey Valley residents in convention appealing to California again asserted they were not part of California and threw in their lot with the Genoa convention asking for their inclusion in Nevada Territory. The U.S. Congress delayed immediate recognition of Nevada Territory.
In July 1859 a new Genoa convention responded by declaring their independence from Utah, and setting up a Nevada Territory provisional constitution. The border with California was cited as the crest of the Sierra from Oregon to 35 degrees north latitude. In September residents voted to approve the constitution and elected Peter Roop as their provisional governor.
In the meantime the discovery of the Comstock Lode and other mineral strikes were drawing a rush of new residents into the area. This demonstrated the need for local government. Finally on 2 March 1861 Congress recognized Nevada Territory. Howver, Nataqua was renamed Roop County.
William Newell Davis, Jr., "The Territory of Nataqua: an Episode in Pioneer Government East of the Sierra," California Historical Society Quarterly 21, No. 3 (September 1942), 225-238 http://www.jstor.org/stable/25161008