Adena (Thomas Worthington House)
Also known as: Mount Prospect Hall
Why it's listed
Adena is a stone mansion and former plantation on a hilltop near Chillicothe, Ohio, built for Thomas Worthington, who became one of Ohio's first U.S. Senators and its sixth Governor. Construction began in 1806, under the name Mount Prospect Hall, and the house was completed the next year. Worthington discussed his plans at length with Benjamin Henry Latrobe and Thomas Jefferson, and Latrobe assisted in the design. The three-part house has a two-story center section flanked by single-story wings that project forward to form a U, with restrained detailing and carefully varied hipped roofs. Gardens, a wash house, smoke house, ice house, servants' cottages, barns and a springhouse once formed a self-sufficient estate surrounded by fields and orchards. The view across the valley is said to have inspired the State Seal of Ohio. The property was given to the State of Ohio in 1946 and is now a museum. It was listed for its political association and architectural merit.
Significance in brief: The nomination argues Adena is significant for its association with Thomas Worthington, one of Ohio's first U.S. Senators and its sixth Governor, and for its architectural merit. Benjamin Henry Latrobe assisted in the design of the Early Federal mansion. The view from the site is said to have inspired the design of the Ohio State Seal.
Machine-generated summary. This summary was generated by a language model from the official nomination document and has not been reviewed line by line by an editor. It may contain errors. Check the source document before relying on any detail. Source: nomination document (PDF) · National Archives catalog entry. NRHP reference 70000515, listed November 10, 1970. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | Box 831 Adena Rd., Chillicothe |
|---|---|
| County | Ross County |
| Listed | November 10, 1970 |
| Reference number | 70000515 |
| Resource type | Building |
| Period of significance | 19th Century; specific date 1807 |
| Architect / builder | Benjamin Henry Latrobe (assisted in the design) |
| Architectural style | Early Federal |
| Areas of significance | Landscape Architecture, Politics/Government, Architecture |
| Level of significance | National, State |
| National Historic Landmark | Yes, designated February 27, 2003 |
| Status (as stated in the nomination) | Excellent and unaltered condition; preserved and restored by The Ohio Historical Society and open to the public as a museum. The large barn and other outbuildings were being restored. |
| Acreage | 300 |
| Coordinates | 39.35522, -83.01360 (NPS GIS) |
What listing means for this property
National Register listing is honorary for a privately owned home: it does not by itself restrict what an owner may do with their own money, and it does not require public access. Restrictions come from local landmark or historic-district ordinances, which are separate (how they differ).
Owner-occupied houses are not eligible for the 20% federal rehabilitation tax credit, which applies to income-producing buildings, but many states offer credits for homeowners. Listing also opens the door to preservation easements and to buying a plaque. Start with what listing means for homeowners, renovating a listed house and selling one.
General information, not legal or tax advice. Rules change; confirm with your State Historic Preservation Office or a qualified adviser.
Sources and further reading
- National Park Service, National Register of Historic Places database (snapshot May 2026), reference 70000515.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q4682182
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.