b. 1815. Allen married Adaline Constant on March 25, 1835. In July 1831, he formed a partnership with William S. Stone to establish a merchant business. Allen and Stone sold dry goods, groceries, hardware, and a variety of other products at their store in Athens, Illinois. The partnership lasted until January 1838. In 1838, Allen formed a new partnership in Springfield, Illinois, with Eli C. Blankenship. Allen and Blankenship's partnership in the dry goods business lasted until April 8, 1841. Allen eventually moved to Shawnee, Kansas.