Benjamin Rush Cowen (August 15, 1831 – January 19, 1908) was Union Army general during the American Civil War and a Republican politician who was Ohio Secretary of State.

[2] Whitelaw Reid in Ohio in the War had this to say of Cowen's service: His first military appointment was that of Engineer-in-Chief, with the rank of Colonel, on Governor Dennison's staff.

This post he resigned on the fall of Fort Sumter, and enlisted as a private in Captain Wallace's company in the 15th Ohio Infantry.

In December, 1863, he was ordered to New Orleans, as chief paymaster of the Department of the Gulf; but before leaving for that post he was tendered the position of Adjutant-General of Ohio, by Governor Brough.

In 1869 he was appointed supervisor of revenue for California, Nevada, Utah, and Arizona, and transferred the following year to the southern district of Ohio.

[2] Grant gave Cowen a number of special assignments, and he is credited with helping to establish Yellowstone National Park.

[1] Cowen became a member of the Literary Club of Cincinnati, and was a frequent public speaker on matters historical and patriotic.