The "Austie" Clark 1911 Mercer Type 35R Raceabout is to feature in RM Auctions' hotly anticipated Monterey sale on August 15-16.
The lot, which has remained in the collection of Henry Austin "Austie" Clark Jr since 1949, is estimated to reach $2.5m-3.5m.
Shelby Myers of RM Auctions commented: "The Mercer name evokes the very spirit of minimalist, sporting automobiles embodied by the 100-mile-an-hour Type 35 series.
"One of America's original sports cars, as a model, the 1911 Mercer can be considered the Ferrari 250 GTO of its day.
"Add in an outstanding ownership provenance, a truly rich patina and character, and the fact that T-head Mercers only change hands on the rarest of occasions, and the stage is set for a truly special auction."
You can keep up to date with all the latest on classic cars by signing up to our free newsletter.