William Slosson Lincoln (August 13, 1813 – April 21, 1893) was a U.S. Representative from New York.

William Slosson Lincoln was born on August 13, 1813, in Berkshire (now Newark Valley), Tioga County, New York, to Otis Lincoln. His father owner a lumber business, saw and grist mills and a tannery. Lincoln attended the common schools. He studied law and was admitted to the bar.^[1][2]

Lincoln worked in mercantile, lumbering and tanning businesses with his father.^[1][2]

He was postmaster of Newark Valley from September 20, 1838, to February 24, 1841, and from December 19, 1844, to September 19, 1866. He served as supervisor in 1841, 1844, 1865, and 1866. He was justice of the peace in 1852 and 1855.^[1]

Lincoln was a Democrat prior to the war.^[2] He was elected as a Republican to the Fortieth Congress from March 4, 1867, to March 3, 1869. He was not a candidate for reelection.^[1] He engaged in the practice of law in Washington, D.C., until his death.^[1][3]

Lincoln married Helen Burbank. They had one daughter, Mrs. Sidney A. Kent.^[3]

Lincoln died on April 21, 1893, at his home at 1714 Massachusetts Avenue in Washington, D.C. He was interred in Oak Hill Cemetery in Washington, D.C.^[1][3]