William Brown McKinley (September 5, 1856 – December 7, 1926) was a United States Representative and United States Senator from the State of Illinois. He was born near Petersburg, Illinois.
After graduating from the University of Illinois at Urbana-Champaign, McKinley became a drug clerk in Springfield. He returned to Champaign to become a banker. In 1902, he was elected a trustee of the university. McKinley ran for U.S. House of Representatives in 1905, winning his first of four consecutive terms. In 1913, he ran for the U.S. Senate against Lawrence Yates Sherman and lost.
He ran for Congress again in 1914 and won, serving from 1915 until 1921. In 1920, McKinley ran against Sherman for the Senate, this time winning. In 1926, he ran for re-election and lost to Frank L. Smith (who ultimately was denied the seat by the Senate on the grounds of fraud and corruption in his campaign), but died on December 7, 1926, aged 70, shortly before his term would have ended.
McKinley was also chief executive of the Illinois Traction System. The McKinley Bridge between Venice, Illinois and St Louis, Missouri was named for him. The McKinley Health Center at the University of Illinois at Urbana-Champaign is also named for him.