William Groneweg (24 July 1838 – 4 August 1928) was a German-born American politician.
He was born in Lemförde to parents William H. Groneweg and Caroline Behning on 24 July 1838.
He divested from retail in 1878 to form a partnership with John Schoetgen as a wholesale grocer.
He served on the Council Bluffs school board, was a Pottawattamie County supervisor from 1868 to 1871, and served as treasurer of Council Bluffs from 1872 to 1876, when he lost an election for Iowa State Auditor to Buren R. Sherman.
Groneweg was elected mayor of Council Bluffs in 1886, serving two years in the office.