Wrigley, William, Jr., Summer Cottage
Also known as: Mt. Ada
Why it's listed
Mt. Ada is a hillside estate about 350 feet above sea level, overlooking Avalon and its bay on Santa Catalina Island. Built in 1921 for William Wrigley Jr. and his wife as a summer residence, it has a two-story, L-shaped, wood-frame main house with stucco exterior and Colonial Revival details. Servants' quarters and a garage sit nearby, and terraced, irrigated gardens surround the buildings. The nomination describes it as the finest residential and garden complex on the island. David M. Renton served as chief architect, Captain A.B. Waddingham as engineer, and Albert Conrad as landscape architect. Wrigley, a chewing gum magnate and owner of the Chicago Cubs, hosted Presidents Calvin Coolidge and Hoover here, and the house became known as the "Summer White House". The estate was opened to the public after Mrs. Wrigley's death in 1958 and donated to the University of Southern California in 1978. Its main buildings remain largely unaltered and it is a local landmark.
Significance in brief: The nomination argues the estate is the finest residential and garden complex on Santa Catalina Island, with high architectural quality and integrity. It was the vacation home of William Wrigley Jr. and his wife, and was visited by Presidents Coolidge and Hoover, earning the name "Summer White House". It is also the finest surviving residence designed by architect David M. Renton.
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 85001785, listed August 15, 1985. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence high).
Key facts
| Address | 76 Wrigley Rd., Avalon |
|---|---|
| County | Los Angeles County |
| Listed | August 15, 1985 |
| Reference number | 85001785 |
| Resource type | Building |
| Period of significance | 1921 |
| Architect / builder | A.B. Waddingham/ David M. Renton |
| Architectural style | Colonial Revival |
| Areas of significance | Landscape Architecture, Architecture |
| Level of significance | State |
| Status (as stated in the nomination) | Described as in good condition and virtually unaltered, apart from the garage, which was converted to living quarters in the 1950s. It was donated to the University of Southern California in 1978. |
| Acreage | 5 |
| Coordinates | 33.34106, -118.32113 (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 85001785.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q14684268
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.