Thunderbird at Writing Rock

Two large granite boulders stand on the Divide County plains twelve miles northeast of Grenora near the Montana border at Writing Rock State Historic Site.

The larger boulder measures four and a half feet high and four feet wide. The State Historical Society of North Dakota describes “a massive, flying bird surrounded by interconnected lines and circles” covering its flattest side. The smaller rock, three and a half feet long, two feet wide, and one and a half feet high, displays a second flying bird connected to abstract designs and what appears to be a headless bird above the other motifs. The historical marker at the site says thunderbird outlines with their wings spread show up on both boulders, and that the image itself turns up on bone and shell ornaments and pottery from the northern plains that are 2000 years old.

The age of the carvings has not been definitively determined. Estimates place them anywhere from 300 to 1,000 years old, or more specifically within a range of AD 1000 to AD 1700, overlapping ranges that reflect ongoing scholarly uncertainty. The State Historical Society says the thunderbird design turns up on prehistoric pottery and on pendants made of shell and bone, not just on rock, and Wikipedia lists similar rock art sites in Saskatchewan, Alberta, Montana, Wyoming, and South Dakota. Petroglyph locations within 200 miles of Writing Rock indicate the site was part of an ancient, established tradition rather than an isolated creation.

Thunderbirds are central to stories told by Algonquian-speaking and Siouan-speaking tribes, according to the State Historical Society. Both the Sioux and Assiniboine considered Writing Rock sacred. Contemporary Dakota and Assiniboine peoples still regard the site as a place of spiritual significance.

American Indian tradition holds that the petroglyphs possessed the power to foretell the future. According to oral history, members of a particular band could read omens in how the images on the rocks changed, but this supernatural ability was said to vanish when the smaller boulder was moved from its original location about 200 feet southwest of the larger rock.

The displaced boulder was kept at the University of North Dakota for many years before being returned to Writing Rock in 1965. The state had acquired the site in 1936 and later recognized it as a state historical site, with preservation efforts beginning in the 1930s.

The historical marker notes that some writers have credited the carvings to prehistoric Norse, Welsh, or Chinese explorers, or read the lines as maps, and that most authorities dismiss those ideas. The State Historical Society is blunter: it calls the designs “clearly American Indian” and the speculation about other origins “unfounded.”

Today, the two boulders are enclosed within a protective shelter and secured behind iron bars. The site offers picnic tables in a grove of trees, covered shelters, a building with kitchen and fireplace, playground equipment, restrooms, and parking, all accessible free of charge with donations welcome. The Williston Graphic says the site is open year-round, and informational plaques explain the petroglyphs.