re: Northfield, MN - My earliest Minnesota cover to date June 27, 1860
Antonio,
Excellent find. Is there a receiving stamp on the back?
And it is in such good condition.
The earliest cover that I have in my processed Minnesota covers is the 1865 St Anthony's Falls card that I posted a while back. I'm still slowly working through my covers, in amongst everything else.
re: Northfield, MN - My earliest Minnesota cover to date June 27, 1860
Well, you certainly have been busy.
There is not a receiving cancel, sad to say. I am not sure when receiving cancels began to be required, but I suspect it is not until later in the 19th century.
It is a little convoluted because of an intertwined discussion of when backstamping of mail addressed to general delivery became practice, and when receiving back stamps became mandatory on any first class mail.