Gerrit Tunis Thorn (July 20, 1832 – February 3, 1900) was an American lawyer and Democratic politician.

[1][2] He received a thorough education, and studied mathematics and civil engineering through the La Fayette Public School and the Yates Polytechnic Institute.

[3] In 1850, Thorn moved to Rome, Pennsylvania, and worked as a clerk and bookkeeper for a store owned by Henry Wells Tracy.

During the winter of 1851–1852, he taught school in Luzerne County, Pennsylvania, after which he returned to New York and attended the Yates Polytechnic Institute.

[3] After teaching school for another season in Watertown, Wisconsin, he resumed his law studies under Henry S. Baird, and then with congressman Charles Billinghurst.

He officially volunteered for the Union Army in August 1862 and was commissioned lieutenant colonel of the 29th Wisconsin Infantry Regiment.

While the regiment was stationed in Helena, Arkansas, Thorn received word that his wife and infant child were seriously ill.

[3] Thorn resumed his legal practice in Jefferson and continued through the 1860s, and was elected to two terms as village president.

[3] In 1869, he left Jefferson for Fond du Lac, Wisconsin, where he became a law partner of Edward S. Bragg.

Due to poor health, he sold his business and his library to James Franklin Ware in 1873, and moved to Maryland.

He finally chose to return to Wisconsin in September 1886, traveling by rail on the newly completed Canadian Pacific Railway, through Winnipeg and Manitoba.