It was well-camouflaged in an eddy on the side of the river, and it looks like it may have been there for a while. If you lost a fly box on the Swift, please get in touch so that I can return it. I called the local MA fly shops already as well. No luck yet.
I suppose this is a public service announcement to put your name and, even better, your address or a phone number on your fly boxes. If this had a name on it, this box would already be back with its owner by now!
Here’s a brookie pic from that quick trip for good measure,