Sidney Edgerton (August 17, 1818 – July 19, 1900) was an American politician, lawyer, judge and teacher from Ohio.

During his term as Territorial Governor, he was an alleged member of the infamous Montana Vigilantes, and was reputedly among its founders.

He had a successful career as a politician, and after his term ended in the Territory of Montana, Edgerton returned to Ohio.

Whereas the young Edgerton avoided death, the same could not be said for his father, a teacher by trade who had been blind for years.

[2][3] He eventually attended the Genesee Wesleyan Seminary in Lima, New York, where his cousin taught, and where he would later become an instructor as well.

[6] The next year Edgerton was admitted to the bar and began the practice of law in Akron, Ohio.

[8] As an ardent anti-slavery member of the House of Representatives, Edgerton made numerous speeches about its abolition.

[14] On his arrival at Charles Town, Edgerton found the commander of Harper's Ferry, General William Taliaferro.

That night, Taliaferro arranged for a wagon to take him back to Washington, D.C. Edgerton was given a driver and a guard, for his journey.

During his ride back, a group of men on horses rode up, and Edgerton's guard jumped out of the wagon and ran.

[8] Edgerton continued to be a large voice in the anti-slavery movement, but decided not to run for reelection in 1862.

Edgerton was one of the Squirrel Hunters, expert shots from Ohio, and served at the Defense of Cincinnati.

[6] On March 6, 1863, Edgerton was nominated by President Abraham Lincoln to be Chief Justice of the Idaho Territorial Supreme Court, and he was confirmed by the senate four days later.

After arriving in South Pass City, Edgerton received a telegraph message saying that the capital of the Territory of Idaho had yet to be decided.

On August 15, as the group was heading west, a man arrived with a telegraph message saying that the capital of the Territory of Idaho was to be at Lewiston.

As the group descended the western slopes of the Rocky Mountains, it was discovered that Mary Edgerton was pregnant.

[25] He was then chosen, by the local population, to go to Washington D.C.[26] His mission was to lobby for the split of the Territory of Idaho.

Numerous engagements between the Governor and Democrats occurred, causing troubles for the Montana Legislature.

[31] In all, though, the legislature worked with Edgerton to pass numerous bills on roads, public education, irrigation, and mining.

He led an expedition against the Sioux and Cheyenne Indians, who were disrupting travelers along the Bozeman Trail.

[28] The revenues being received were not enough to pay for expenses, and Edgerton himself gave large sums of his own money to the territory.

[6] During this time, Edgerton was in Washington, D.C.[31][35] While he was away, Thomas Francis Meagher served as the acting Territorial Governor of Montana.

[28] After numerous acts of lawlessness, and with no established court system, Edgerton supported his nephew, Wilbur F. Sanders, and other residents of Bannack and Virginia City as they organized the Vigilantes.

On January 10, 1864, members of the Vigilance Committee traveled to Sheriff Henry Plummer's home.

Then the men put a noose over his neck, and hanged him next to two of his deputies who were also accused of being road agents.

[39] After these actions Edgerton's nephew, Wilbur F. Sanders, was forced to defend the group in Utah courts.

[31] After returning to Akron, Ohio, with his family in the Fall of 1865, Edgerton went back to his law practice.