Wilson Colwell, a Pennsylvania native, was born in 1827. He was the son of Alexander and Margaret (Henry) Colwell, natives of northern Ireland and of Scotch-Irish ancestry. Colwell came to La Crosse in 1856 and founded the city's first bank, the Katanyan Bank. Colwell owned it and served as its president.
In 1858, he married Nannie Hammer, and their only child, Nannie Colwell, was born in 1859. In 1860 he and Nannie purchased property in La Crosse at present day 330 So. 6th St. He was elected mayor in 1861. In April of that year, Colwell enlisted in the U.S. Army as Captain of the Light Guards who then came to be known as Company B, 2nd Wisconsin of the Iron Brigade. Colwell was killed in the Battle of South Mountain, September 14, 1862. The Katanyan Bank crashed shortly after his death.
