Seventh Cavalry's first clash with the Sioux near the Tongue River

Background. The Yellowstone Expedition of 1873 aimed to survey a route for the Northern Pacific Railroad along the Yellowstone River. Custer and units of the 7th Cavalry were part of the military column commanded by Colonel David S. Stanley, accompanying the survey party in eastern Montana. The expedition entered Montana Territory in July 1873, setting the stage for conflicts with Lakota Sioux.

The Clash. On August 4, 1873, near the Tongue River, the 7th Cavalry Regiment clashed for the first time with the Lakota. Separately, the Battle of Honsinger Bluff is described as a conflict between the United States Army and the Lakota on the same date along the Yellowstone River near present-day Miles City, Montana; this has been proposed as an identification with the Tongue River clash, though the supplied passages do not explicitly link the two localities. The conflict involved Native Americans from the village of the Hunkpapa, who would later confront Custer at the Battle of the Little Bighorn.

Aftermath and Context. The battle hindered collecting activities in the immediate region, making it unsafe to go far from the command. The conflict was part of broader tensions between the U.S. and Plains Indians tribes. The expedition returned to Dakota Territory in late 1873, ending on September 23, 1873.