“Yellowstone” is the oldest and most important of the park’s place names, dating back to the late eighteenth century. The name was first applied to the 671-mile-long river that begins just south of the present park and flows into the Missouri River at present-day Williston, North Dakota.The earliest known appearance of the name occurs on John Evans’ manuscript map of 1797. Evans, a Welshman employed by Spaniards to explore the Missouri River, showed a tributary stream as “River Yellow Rock.” Historian Hiram Chittenden considered the name a translation of the Minnetaree Indian expression Mi tsi a-da-zi, which was transformed in French to Roche Jaunes (Rock Yellow) or PierreJaunes (Stone Yellow). Later, in 1798, the French version was Anglicized by Canadian geographer David Thompson to “Yellow Stone.”

Although Chittenden believed that the name “Yellowstone” originated from the colorful walls of the Grand Canyon of the Yellowstone River within the present national park, most historians today do not agree. Their reasoning is that the earlier historic uses of the name referred to the yellowish sandstone bluffs that border the river for 100 miles or more near present-day Billings, Montana. It is unlikely that the Minnetaree Indians or the early EuroAmericans knew of today’s famous canyon near the headwaters of the river.

The source of the Yellowstone River is found on the slopes of Yount’s Peak, southeast of the park. Geologist Arnold Hague traveled to the spot in 1887 and reported that the source of the river was “in a long snow-bank lying in a large ampitheatre on the north side of the [Yount’s] peak.” The river flows through Yellowstone Lake, the largest natural freshwater lake above 7,000 feet in elevation in the United States. The lake is 20 miles long and 14 miles wide, has a shoreline of 110 miles, and is at least 320 feet deep, with an average depth of 140 feet. After leaving the lake, the river flows through four canyons on its journey to the Missouri River: the Grand Canyon (where Upper and Lower Falls are found), the Black Canyon, Yankee Jim Canyon (just north of the park boundary), and Rock Canyon (just south of Livingston, Montana).

Through association with our first national park, the name “Yellowstone” has assumed a significance that goes far beyond its importance as a place name for a river. The name has become synonymous with much that is basic to the national park idea.