Trimborn Farm is a Victorian era estate located in Greendale, Wisconsin, United States, and owned by Milwaukee County.

[2] In 1851, Werner Trimborn and Jacob Kier purchased O'Donnell's lime-production business which covered ten acres (25 ha) on site.

[4] In 1919, the Froemming family purchased a large tract of land to build greenhouses on, a portion of which was later donated to Whitnall Park.

[4] In 1935, the farm, along with 3,400 acres (8.4 km²; 8400 ha) of surrounding land, was purchased by the federal government as part of a planned agricultural community known as the Greendale Project.

After the Great Depression, the remaining farmland passed into private ownership, where it became home to crop dusters and a riding stable.