|Provisional Governor of the Proposed Territory of Nevada|
December 15, 1859 – March 2, 1861
|Succeeded by||James W. Nye (as Territorial Governor)|
|Born||March 13, 1822|
Carroll County, Maryland, U.S.
|Died||February 14, 1869 (aged 46)|
Susanville, California, U.S.
|Resting place||Susanville Cemetery|
|Spouse(s)||Nancy (nee Gardner) Roop|
|Occupation||Farmer, trader, politician|
|Known for||Early settler of Susanville, California|
Isaac Newton Roop (March 13, 1822 – February 14, 1869) was a United States politician, pioneer, and a lifelong member of the Whig party. In 1859, he was the first elected (provisional) governor of the newly proposed Nevada Territory.
In 1851 William Nobles (guide) started taking settlers over a route through the Sierra Nevada passing through the Honey Lake valley; included among these settlers were the 29-year-old Isaac Roop and his family. His first three years in California were spent in Shasta County, in farming and trading. During this period he also held the positions of Postmaster and School Commissioner. He had accumulated in that time upwards of fifteen thousand dollars' worth of property, but in June 1853, lost it all by fire. It was then that Roop retreated to the Sierra Nevada and to Honey Lake, where he concentrated on his own backcountry holdings and nearly single-handedly erected the burg of Rooptown which he would later name for his daughter Susan.
In September 1859, Roop was elected the first territorial governor of the proposed Nevada Territory. At the time, Susanville was thought to be in Nevada instead of California. The new provisional government first convened on December 15, 1859, in the town of Genoa. Roop lived in the contested County of Roop. He was elected in 1861 to the new Nevada Territorial Senate.
On December 24, 1840, Roop married Nancy Gardner, his tutor. They have 3 children, John, Isaiah, and Susan. On June 20, 1850, Roop's wife died of typhoid fever.
In 1865, Roop lived in Susanville, California. On February 14, 1869, Roop died in his residence in Susanville, California.  His daughter Susan Arnold resided in the town as well until her own death in 1921, and both were buried in the town's cemetery. There is a mural depicting father and daughter in uptown Susanville, on the outside wall of Johnson's Shoes.
- Bruce, A. T. (1869). "Isaac Roop". Lassen Sagebrush. Retrieved November 16, 2010.
- "Isaac Roop". Ancestry.com. Retrieved 26 September 2012.
- "Isaac Roop". Lassen County, California GenWeb Project. Retrieved 26 September 2012.
- "Creation of Nevada's Counties". Nevada Association of Counties. Archived from the original on February 22, 2012. Retrieved September 25, 2012.
- Butler, James Thomas (1994). Isaac Roop, Pioneer & Political Leader of Northeastern California. Susanville (California): High Desert Press. ISBN 0-936029-40-4.
- Isaac Roop at Find a Grave
- Isaac Roop at WesternStarWiki
- Lassen County, California GenWeb Project
| Provisional Governor of the Proposed Nevada Territory
1859 – 1861
James W. Nye