Near Simms in Cascade County, Montana — The American West (Mountains)

Bird Tail Rock

Photographed by Barry Swackhamer, August 20, 2019

1. Bird Tail Rock Marker

Inscription. Bird Tail Rock to the southeast was one of the most prominent landmarks along the Benton Road between Fort Benton and Helena. An igneous intrusion about 55 million years old, it acquired its name because it resembled a "bird's tail" erect and spread out in a fan-shape. "Following an old Indian Trail, Lieutenant John Mullan built a road past this extraordinary geological feature in July 1960. The rock was located on a steep divide about midway between the Sun River and Dearborn River crossings. At first, Mullan was not sure wagons could be able to traverse the rugged terrain here. But after pulling a two-wheel cart over the divide in 1859, his assistant, P.M. Engel, determined the route "practicable for wagons in its present state." With the discovery of gold in southwestern Montana in the early 1860s, the road now known as the Benton Road, was heavily used by freighters and stagecoaches traveling between Fort Benton and Helena. In 1881, a traveler on the road reported that Bird Tail Divide "was more or less dangerous... and perhaps the lost trying piece of stage road in northwestern Montana during the winter season, as

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the snow-drifts frequently obliterated all traces of (it) for miles."

Erected by Montana Department of Transportation.

Topics. This historical marker is listed in these topic lists: Landmarks • Natural Features • Roads & Vehicles.

Location. 47° 20.13′ N, 112° 4.613′ W. Marker is near Simms, Montana, in Cascade County. It is on State Highway 200 at milepost 114 near U.S. 287, on the right when traveling west. Touch for map. Marker is in this post office area: Simms MT 59477, United States of America. Touch for directions.

Regionally, this marker is in andspecifically entral Montana in Russell Country. It is also in the American Mountain West

and in the Lewis & Clark Corridor.

Globally, it is in North America,

the Rocky Mountains,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once Rupert’s Land

and also the Louisiana Purchase.

Other nearby markers. At least 3 other markers are within 17 miles of this marker, measured as the crow flies: "nearer than the route we Came" (approx. 16.3 miles away); Bighorned Animals

Bird Tail Rock and Marker image. Click for full size.

Photographed by Barry Swackhamer, August 20, 2019

2. Bird Tail Rock and Marker

(approx. 16.3 miles away); Join the Voyage of Discovery (approx. 16.3 miles away).

Credits. This page was last revised on February 14, 2026. It was originally submitted on January 1, 2020, by Barry Swackhamer of Brentwood, California. This page has been viewed 3,387 times since then and 242 times this year. Photos: 1, 2. submitted on January 1, 2020, by Barry Swackhamer of Brentwood, California.