Civil War Union Army Officer, US Congressman. Born in Westernport, Maryland, he received a classical education at the estate of his father's friend, former Maryland governor Francis Thomas. While studying law under Thomas he interrupted those studies and enlisted in the Union Army after the outbreak of the Civil War, and was mustered in as a Private in Company C, 3rd Potomac Home Brigade, Maryland Volunteer Infantry on September 12, 1861. Promoted to 1st Lieutenant on January 1, 1862, it began his rise in the ranks that culminated in his being commissioned Colonel and commander of the regiment on September 8, 1862. He was captured with his unit at Harper's Ferry, Virginia when it capitulated to Confederate forces under Major General Thomas "Stonewall" Jackson on September 15, 1862. Paroled the next day, he eventually resigned on November 6, 1862 due to poor health. After the Civil War, he practiced law in Washington D.C. before returning to Maryland in 1865, practicing law there and in West Virginia. He moved with his wife and two daughters to Laramie City, Wyoming Territory, in 1869. Soon after he was appointed Albany County Attorney, and filed the first of many mining claims. In his role as county attorney he impaneled a grand jury in March 1870, the first in the world which seated women along with men. He was elected to a full term as county attorney and in 1871 served the first of seven terms in the Wyoming Territory and later Wyoming State legislatures. In 1872 he was appointed Wyoming Territory Auditor. He became involved in mining, but despite starting out with great promise, the endeavors returned no profit. In 1878 he was elected as a Delegate from the Wyoming Territory to the United States House of Representatives, serving a single term from 1879 to 1881. Running his law practice and continuing the elusive search for gold kept him busy for the next several years. In 1886, while in the territorial legislature, he was largely responsible for passage of the act which created the University of Wyoming, earning him the title "Father of the University." From 1891 to 1897 he served as president of the University of Wyoming Board of Trustees, seeing it though tough financial times. Elected the last time as county attorney in 1900, he died less than two years later, leaving nearly penniless due to numerous pursuits of mining riches. His son Sheridan Downey became a United States Senator from California.