The site of the Battle of the Little Bighorn (25 June 1876), about 65 miles east of Billings via I-90, is one of the most historically significant and atmospherically powerful places in the American West. White marble headstones mark where soldiers fell across the rolling grassland; red granite markers show where Lakota, Cheyenne, and Arapaho warriors died.
The visitor centre has excellent exhibits on both sides of the battle, and guided tours add considerable depth to what you see in the landscape. The view from Last Stand Hill across the undulating grassland toward the Wolf Mountains is genuinely affecting. Budget two to three hours, including the drive. The National Park Service site is open year-round.