The 6-cent Fort Snelling commemorative postage stamp was first placed on sale at Fort Snelling, Minnesota, on October 17, 1970.
The stamp was issued in conjunction with the fort's 150th anniversary. Located in Minnesota, the fort was instrumental in pioneering the opening of the Northwest.
The stamp was designed by David K. Stone, issued in panes of fifty, with an initial printing of 135 million.
Postal Bulletin (September 17, 1970).
Minnesota Historical Society. "Historic Fort Snelling." http://www.mnhs.org/places/sites/hfs/history.html