US Congressman, Mexican-American War Brigadier General. Elected to represent Ohio's 5th District in the Twenty-Third and two succeeding Congresses, he served from 1833 to 1839. He was elected to a fourth Congressional term in 1846 but died in military service before taking his seat. Hamer was born in Northumberland County, Pennsylvania. At age 17 he moved to Ohio, where he was admitted to the bar in 1821 and set up practice in the newly-founded Georgetown, Brown County. He was a member of the State House of Representatives in 1825, 1828, and 1829, serving as Speaker in the last year. Hamer won his first two terms in the US House of Representatives as a Jacksonian but switched to the Democratic Party for the Twenty-Fifth Congress (1837 to 1839); he did not seek reelection and returned to Georgetown. In 1845 he declined an offer from President James Polk to become Commissioner of Indian Affairs. With the outbreak of the Mexican-American War Hamer was appointed Brigadier General and placed in command of the 1st Brigade of Major General William O. Butler's Volunteer Division, US Army of Occupation. He fought with distinction in the Battle of Monterrey (September 1846), assuming command of the division after Butler was wounded, and when Mexican General Pedro de Ampudia offered to surrender Hamer delivered the message to Army Commander Zachary Taylor. He died while stationed in Monterrey, probably of dysentery, and may not have known that he had been reelected to the US House without opposition. Taylor lamented, "I have lost the balance wheel of my volunteer army". Congress issued a resolution of sorrow and presented his nearest male relative with a sword. For all his distinguished service, Hamer is perhaps best remembered today for a clerical error. During his last months in Congress he nominated the son of a constituent, Hiram Ulysses Grant, to become a cadet at West Point, but mistakenly entered him as "Ulysses Simpson Grant". The future Civil War Union General and US President adopted this name for life. In his memoirs Grant praised Hamer as "one of the ablest men Ohio ever produced".