William Ignatius Nolan (May 14, 1874 – August 3, 1943) was a politician from the U.S. State of Minnesota. He represented the state in the U.S. House of Representatives. Nolan was born in Saint Paul, Minnesota and served in the Minnesota National Guard from 1891 to 1896. He was member of the Minnesota House of Representatives from 1903 to 1907, 1911–1913, and 1917–1923, serving as speaker from 1919–1923. He was Lieutenant Governor of Minnesota from 1925–1929. Nolan was the chairman of the Minnesota Reforestation Commission in 1927.