Samuel Clarke Pomeroy (January 3, 1816 – August 27, 1891) was a United States senator from Kansas in the mid-19th century. He was in the United States Senate during the American Civil War. Pomeroy was also in the Massachusetts House of Representatives.He also was the mayor of Atchison, Kansas from 1858 to 1859. He was also the second president of the Atchison, Topeka and Santa Fe Railroad, and the first president to oversee any of the railroad's construction and operations. Pomeroy succeeded Cyrus K. Holliday as president of the railroad on January 13, 1864. He was a Republican.