Ormsby Brunson Thomas (August 21, 1832 – October 24, 1904) was an American lawyer, Republican politician, and Wisconsin pioneer.

Ormsby Thomas was born in Sandgate, Vermont, but moved to the Wisconsin Territory with his parents when he was a young child.

[2] He became active in local politics and was elected district attorney of Crawford County in 1858, running on the Democratic Party ticket.

[4] When the American Civil War started, in 1861, Thomas was the incumbent district attorney in Crawford County and was running for Wisconsin State Assembly.

[5] After the end of the 1862 legislative session, Thomas went to work raising a company of volunteers for the Union Army from Crawford County.

For the first several months of their service, the regiment was solely tasked with training for battle, supervising conscription of draftees, and guarding Confederate prisoners of war at camps in Wisconsin.

[7] On returning to Wisconsin, Thomas was elected to another term in the Assembly, but was now running on the National Union Party ticket.

Thomas served in the Union caucus in the 1865 session of the Legislature and remained associated with the Republican Party for the rest of his life.

[9] After the legislative session in 1867, Governor Lucius Fairchild appointed Thomas to fill the vacant district attorney post in Crawford County, following the resignation of Joseph M.

He was defeated seeking a fourth term in 1890, in the wave election that saw Democrats claim 8 of Wisconsin's 9 congressional seats.

[19] In 1898, Thomas accepted the Republican nomination for another term as district attorney of Crawford County, and was elected in the Fall.