When a post office was established in this locale, it was named for the Rev. Joseph Ritter, a pioneer Baptist minister of the John Day Valley, on whose ranch it was situated. The post office was originally near the mineral hot springs there, formerly known as McDuffee Hot Springs but now known as Ritter Hot Springs. In 1988, the post office had moved to the old schoolhouse across the river. As of 2009, Ritter no longer had its own post office; Ritter's mail is addressed to Long Creek.
The springs were discovered by William Neal McDuffee, an early-day packer who traveled between Umatilla and the John Day Valley mines.