Picked this cover up recently and am trying to pin down exactly when it was cancelled, which I fear is hopeless.
Fort Ridgely, Minnesota existed from 1853/54(opened) and closed in 1867. The 67 closure seems to rule out all of the Scott #79 and 94's but still leaves at least a five year run for the 64's and 65's. The picture is very very close to real life on the color- guessing this is a rose or rose brown of some kind and not pink at all.
The Sioux Uprising or War began August 18, 1862 and Fort Ridgely was attacked on the 20th and 22nd. So if this is an August 27, 1862 cancellation it becomes a very big deal to those of us who worry about such things.
If it is from another year it is still quite unusual and interesting but maybe not as significant as 1862 would be. The fort is pretty tough to collect for anything original so glad to find this either way.
BTW- the Sutler aka P.O. was a putz! He figured out the F.R.military reservation was unplatted (the Gov forgot to claim it) so in 1861 he got title to the land. His case went all the way up to US Grant in 1866 who said if he did this while sutler fire him NOW.*** Moved by Staff to a more appropriate forum. ***