William Chamberlain Duncan (May 18, 1820 – December 19, 1877) was a brewer, politician, and mayor of Detroit, Michigan.

[1] The family moved to Rochester, New York in 1825, and in 1841 Duncan began working as a steward[2] on the passenger steamers crossing the Great Lakes.

[2] He was mayor of Detroit for two years, 1862 and 1863, and in the fall of 1863 was elected as a Democrat to the Michigan State Senate, where he represented the 2nd district.

[1][3] He began in the banking business in 1865, but soon gave up the trade due to impaired health[2] and to take care of the property he had accumulated and to visit Europe.

[2] In the same year, the city Democratic Party asked him to again be their candidate for mayor, but Duncan declined due to his ill-health.