The 1851 United States Senate election in New York was held on February 4 and March 18–19, 1851, by the New York State Legislature to elect a U.S. Senator to represent the State of New York in the United States Senate.

Hamilton Fish was an American politician and statesman who served as the 16th governor of New York from 1849 to 1850, a United States senator from New York from 1851 to 1857, and the 26th U.S. secretary of state from 1869 to 1877. Fish was the most trusted advisor to President Ulysses S. Grant and recognized as the pillar of Grant's presidency. He is considered one of the nation's most effective U.S. secretaries of state by scholars, known for his judiciousness and efforts towards reform and diplomatic moderation. He settled the controversial Alabama Claims with the United Kingdom, developing the concept of international arbitration and avoided war with Spain over Cuban independence by coolly handling the volatile Virginius incident. He also organized a peace conference and treaty between South American countries and Spain. In 1875, Fish negotiated a reciprocal trade treaty for sugar production with the Kingdom of Hawai'i, initiating the process which ended in the 1893 overthrow of the House of Kalākaua and statehood. Fish worked with James Milton Turner to settle the Liberia-Grebo War in 1876.