Orville Hitchcock Platt was a United States Senator from Connecticut. Platt was a prominent conservative Republican and by the 1890s he became one of the "big four" key Republicans who largely controlled the major decisions of the Senate, along with William B. Allison of Iowa, John Coit Spooner of Wisconsin and Nelson W. Aldrich of Rhode Island.
He was clerk of the Connecticut Senate in 1855 and 1856, Secretary of the State of Connecticut in 1857, and a member of the State senate in 1861 and 1862. He was a member of the Connecticut House of Representatives in 1864 and 1869, and served as speaker in the latter year. The former Platt National Park in Oklahoma was named for him. Platt was state's attorney for New Haven County from 1877 to 1879 and was elected as a Republican to the U.S. Senate in 1879. He was re-elected in 1885, 1891, 1897 and 1903 and served from March 4, 1879 to his death. He was chairman of the Committee on Patents and a member of the Committees on Pensions, Territories, Cuban Relations, and the Judiciary. By the 1890s, Platt's influence in the Senate swelled to the point that eventually, he was known as a member of the "Senate Four" who largely controlled the Senate, along with John Coit Spooner, William B. Allison and Nelson W. Aldrich. Because of his votes against the Sherman Anti-trust Law, the Eight-Hour Labor Act, and the Anti-Injunction Bill, Platt was denounced by the labor organizations and was considered a reactionary. He was an earnest advocate of the abolition of secret executive sessions of the Senate. On March 1, 1901, the U.S. House of Representatives passed the Army Appropriation bill with the Platt Amendment as a rider, which governed U.S. relations with Cuba from 1901 to 1934 and was named for Platt. He was a Compatriot of the Sons of the American Revolution.
In 1902, Platt introduced legislation to establish the 640-acre Sulphur Springs Reservation, protecting about 30 mineral springs, in Murray County, Oklahoma. On June 29, 1906, Congress redesignated the reservation as Platt National Park, named for the senator. It remained the smallest national park in the United States until it was abolished by Congress and made part of the much larger Chickasaw National Recreation Area in 1976. Yale gave him the degree of LL.D. in 1887. Platt died on April 21, 1905, aged 77, in Meriden, and was interred in Washington, Connecticut in the Cemetery on the Green. One of the two Public High Schools in Meriden was named for Platt.
