Lyon was born in Connecticut in 1818 and graduated from West Point in 1841. From 1854-1861 he was stationed in "Bleeding Kansas." After February, 1861 he commanded the Federal arsenal at St. Louis. On May 17, 1861 he was promoted to brigadier general. In the following months, he attempted to drive the pro-Confederate elements from Missouri. On August 10, 1861 he was killed at the battle of Wilson's Creek, near Springfield, Missouri.

Source: "Generals in Blue" Warner, Ezra J.