Jacob Weidenmann (1829 – February 6, 1893) was an American landscape architect.
After graduating, he worked in Munich, Paris, London, New York City, Panama, and Peru, before settling in the United States in 1856. In 1861 he was named first superintendent of parks in Hartford, Connecticut, where he designed Bushnell Park and Cedar Hill Cemetery. In 1874 he became a collaborator with Frederick Law Olmsted on projects including Mount Royal Park in Montreal, and the Washington, D.C., Capitol grounds.
Weidenmann's Hartford designs include grounds for the American School for the Deaf, Bushnell Park, the Butler-McCook Homestead gardens, Cedar Hill Cemetery, and the Institute of Living. His Midwest designs include the Iowa State Capitol, Iowa State Fair Grounds, and Chicago's Mount Hope Cemetery. His national work included landscape designs for the United States Capitol, U.S. Quartermaster Depot, Schuylkill Arsenal, and Hot Springs Reservation.
He died on February 6, 1893.
- Beautifying country homes, Orange Judd, New York, 1870. Reprinted as Victorian Landscape Gardening: A Facsimile of Jacob Weidenmann's Beautifying country homes, American Life Foundation for the Athenaeum Library of Nineteenth Century America, 1978. ISBN 0-89257-021-0.
- Modern cemeteries. An essay upon the improvements and proper management of rural cemeteries, The Monumental news, Chicago, c1888.