Followers of my writing may remember the controversy over where the Mitchell, Alaska, post office was located. The mail received there was almost always for U.S. citizens living in Canada. The Mitchell Post Office cancellation is one of the most sought after postal stamps in the postal collectors' world because its location is such a mystery.
One old writer said it was actually in Captain Jack's store in Forty Mile (in Canadian territory). Others have said it was about 70 miles over the line. Ed Jones surmised that there was a miner there at the time, in Alaskan territory, named Mitchell, and Jack may have been using his camp as the pseudo post office "office."
Well, in the new book I just purchased of old writings about the Yukon a contemporary writer describes how U.S. mail would enter Canada over one of the passes south of the Yukon, and be sailed through lakes and streams northward, passed Dawson and on to the U.S. post office back in Alaska.
What this means is that mail destined for Mitchell would have been off loaded from the mail boat at Forty Mile regardless, and so it is likely Jack just passed it out there rather than travel over the border and back with it just to make it official. When he filed a report with the postal service, he was extremely vague on the actual location of Mitchell.
I think it was a matter of convenience. Circle City wasn't founded by Jack yet, and the next closest U.S. Post Office would have been so far away as to make it impractical to go there on any regular basis. This way, he had the U.S. postal service bring the mail right up to Forty Mile, whether or not it was carried across the border and back, or not. Even coming in this way, the typical trek for mail into the Yukon could last months, especially in the winter. So any postal worker in his right mind would be thrilled to have Jack take the mail at Forty Mile instead of walking or sledding the additional 70 miles or so to a mythical post office, just to see it returned to where they started at Forty Mile.