The 1904 National Convention of the Republican Party of the United States was held in the Chicago Coliseum, Chicago, Cook County, Illinois, on June 21 to June 23, 1904. The popular President Theodore Roosevelt had easily ensured himself of the nomination, though a threat had come from the Old Guard favourite Ohio Senator Mark Hanna, the loyal kingmaker in Republican politics. But the senator had died early in 1904 therefore ending all opposition in the Republican Party.