Whole houses whose own listing states a build year before 1900, or a National Register listing, in so many words.
The standard is the manager's own listing text: a stated build year before 1900, or a stated National Register listing or named historic district with a date. StayClubs holds the club until a preservation audience takes it.

Plenty of listings say historic. Very few say when. This club takes only the ones that put a date on it: the manager's own page states the house was built before 1900, or names its National Register listing. Nothing here is inferred from style, street, or a county record. If the listing does not say the year, the house is not in.
Twelve homes from nine managers across ten states, grouped by region. Each links to the manager; you book with them.
Rhode Island, Massachusetts, Vermont, Maine.
Preview from Vacasa's listingCape May, New Jersey and Ocracoke, North Carolina.
Preview from Jersey Cape Realty's listingSavannah, Charleston, and the Texas coast.
Preview from Vacasa's listingSoutheast Michigan.
The common failure is the word historic with no date. These pages loaded and were read; they are listed so nobody re-checks them.