Hanna is an unincorporated community in western Duchesne County, Utah, United States, on the Uintah and Ouray Indian Reservation.
The community lies along State Route 35 (SRâÂÂ35) and the Duchesne River, approximately northwest of the town of Tabiona and northwest of the city of Duchesne, the county seat of Duchesne County. Its elevation is . Although Hanna is unincorporated, it has its own ZIP code of 84031 and, for many years, even had its own post office.
Hanna was named for its original postmaster, William P. Hanna. Historically, the name Defas Park (a former resort in Hanna, with a dance hall and cabins) often appeared on maps at the location of the community, with the name Hanna appearing at a location further west. However, the former post office was located along SR-âÂÂ35, but about northwest of the main community.
This climatic region is typified by large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold) winters. According to the Köppen Climate Classification system, Hanna has a humid continental climate, abbreviated "Dfb" on climate maps.