Oneco's Johnson Helm House Becomes Manatee County's First Local Historic Landmark

A century-old mansion in Oneco has become the first property in Manatee County history to earn local historic landmark status, a designation that now legally shields the home from unapproved exterior changes or demolition. The Johnson Helm House, built between 1906 and 1908, sits on a 0.91-acre parcel at 2104 53rd Avenue East along State Road 70, and the Manatee County Board of County Commissioners approved its new status this week.

According to Manatee County, Florida Government, the designation recognizes decades of preservation work by the home's current owners and by Oneco community members who pushed to protect the property. The Bradenton Times reports that owners Margi and Pat Nanney, who bought the house in 1985 and have lived there for 41 years while restoring it, spearheaded the local landmark application, which the Board of County Commissioners approved unanimously by a vote of 5-0.

What Landmark Status Actually Changes

The Johnson Helm House has been listed on the National Register of Historic Places since September 2, 2009, under reference number 09000671, according to Wikipedia. But federal recognition is largely honorary and does not stop a private owner from altering or tearing down a historic structure. Local landmark status is different: per Manatee County Government, designating a site as a local historic landmark places it inside a Historical and Archaeological Overlay District under the county's Land Development Code Section 347 and Chapter 403.5, which legally requires any future exterior alterations, additions, or demolitions to go through review and obtain a Certificate of Appropriateness from the Historic Preservation Board.

The Manatee County Government notes the new status provides an additional level of review intended to help protect the home's historic character. Before it reached the county commission, the nomination went through a public hearing before the five-member Manatee County Historic Preservation Board on June 18, 2026, and the county administers its local preservation program through its status as a Certified Local Government, a joint state-federal arrangement that lets municipalities designate historic sites and tap matching state survey and preservation grants.

A House Built on Molded Concrete and Grapefruit Money

The three-story residence was constructed by contractor J.S. Maus with an irregular floor plan built largely of ornamental molded concrete block, a two-story southwest corner tower, and a one-story circular projection on the northeast corner, according to the National Park Service. Manatee County, Florida Government describes the home as an example of Romanesque Revival architecture featuring ornamental balustrades, an ornamental staircase, detailed woodwork, and original flooring that survive to this day.

The house takes its name from Johnson Helm, who moved to the site in 1877 from Indiana with his father, John M. Helm, after the elder Helm cleared the land for orange groves, per Wikipedia. Johnson Helm went on to become a prominent local grapefruit farmer and, according to Manatee County, Florida Government, a stockholder and president of the Bank of Manatee. The property is also listed on the Florida Master Site File.

Preservation Fight Followed a Nearby Development Battle

The push for local protection followed a contentious 2024 land-use fight just down the road. In August of that year, the Manatee County Planning Commission voted unanimously, 7-0, to deny a developer's request to rezone a neighboring 6.4-acre parcel at 2008 53rd Avenue East for a 116-unit residential complex, after the community group Citizens for Historic Oneco argued the proposed three-story development would sit just 40 feet from the Johnson Helm House, according to a petition on Change.org. Residents at the time warned that dense construction would worsen stormwater flooding along Pearce Drain and damage the historic setting of the property.

Citizens for Historic Oneco has described the Johnson Helm House as the only surviving original residential landmark from Old Oneco's initial late-19th-century settlement period, per the same Change.org petition. Old Oneco was established as an agricultural community in 1881, roughly five miles southeast of early Bradenton, and the Johnson Helm House remains tied to that early chapter of local history, according to Manatee County, Florida Government.

County officials congratulated the Nanney family for its role in preserving the home, per Manatee County, Florida Government. With the new designation now in place, the Johnson Helm House stands as the first property to pass through Manatee County's local historic preservation process, and future owners will be bound by the same review requirements the Nanneys helped put in place.