William Brown (June 1, 1819 – January 15, 1891) was an English American businessman and politician.
Initially a public school teacher, Brown was soon elected a justice of the peace.
In 1852, Brown was elected state's attorney for Winnebago, Stephenson, and Jo Daviess Counties, serving three years.
From 1857 to 1860, he practiced law with future United States Representative William Lathrop.
In 1864, Brown was elected as a Republican to the Illinois House of Representatives, serving one two-year term from the 55th district.