Millionaire brewer Robert Portner (1837-1906) built Annaburg in 1892, naming it after his wife, Anna, and Annaburg Castle on the Rhine River in his native Germany. It's described as a Classical Revival structure with Prussian influence designed by architect Gustav Friebus who also drafted plans for the Washington Monument.
In its day, this 2,000-acre property was a central feature and the pride of Manassas hosting the annual Piedmont Virginia Dairy Festival, Fourth of July fireworks, and welcoming the community in the winter to ice skate on the estate’s pond.
Today, the house sits on 3.65 acres and is the City’s newest park, which opened in 2019. From dawn to dusk, the grounds are open for walks, picnics, and special events. Recognizing its historical and architectural significance, the Virginia Department of Historic Resources placed Annaburg on the Virginia Landmarks Register in December 2021. In April 2022, the site was included in the National Register of Historic Places by the National Park Service.
Annaburg now joins other City-owned properties listed on the National Register of Historic Places: Liberia, Manassas Industrial School, Cannon Branch Fort, Mayfield Earthwork Fort, the Manassas Water Tower, and the Downtown Manassas Historic District.