Sentinel Butte is among the highest points in the state, reaching a maximum elevation of 3430 feet. The butte is a large flat-topped
butte or mesa which rises approximately 600 feet above the surrounding countryside.
Sentinel Butte is believed to be named for two Arikaree Indian sentinels or scouts (American Black Eagle and Standing Together) who were slain in this area.
The butte is divided by a saddle into two plateaus of 240 acres total. The nature preserve, owned by the Department of Transportation makes up only 4 acres of the butte. All surrounding lands are under private ownership. The vertical cliffs and steep rocky slopes grade into mixed grass prairie on the lower slopes. Small pockets of woodland are located on the north side below cliffs and in draws.
The butte has been carved from rock strata of the Sentinel Butte Formation of which the top 80 feet are sandstone. Topping the sandstone on each mesa is a layer of soft white to grey limestone and clay. These rock beds, referred to as the White River Formation, contain the fossil fish that are object of protection of the nature preserve. There are eight Natural Heritage elements found within the Sentinel Butte State Nature Preserve; two of which are fossil fish found on Sentinel Butte. Phioplarchus whitei and P. sexspinosus, are unique to the site-two species of sunfish found nowhere else in the world. Other elements reported to have been seen or sought after within the nature preserve are: mixed grass prairie natural community, smooth cliff-brake, phlox, fleabane and golden eagle sightings.
Sentinel Butte Nature Preserve is located 3 miles south of the town of Sentinel Butte.
Map Navigation: Click on the + sign to zoom in, the - sign to zoom out, or hold the right click mouse button down and move your mouse to pan the map (drag and drop).