Wow! That box is in good shape. It looks hardly used. It is similar to the one we had in the 1940s in southern Illinois. Rural electrification came to that area in 1947 (after WW2) ending the iceman's delivery and the icebox. Most iceboxes were discarded because a refrigerator was a vast and welcome improvement and less costly. I remember that our first month's electric bill (for everything) was less than what we had been paying for ice.

Places to look for identification:

1. top side

2. Back side

3. Bottom

4. A stamped logo on the inside.

5. Lift out the metal drip pan to see if any id was under it.

It is possible that your box was not manufactured but home-made by a handy cabinet maker. There is no fancy mechanicals. The major requirements are: Insulation, rot resistent materials, and a water tight drip pan and drain. The pan must be rust resistant and safe around foods. It should not have any lead bearing solder - most solders of the time were lead alloys. The usual material for the ice/drip pan was zinc. A galvanized steel pan could be used, but a 100% zinc pan was more corrosion resistent,

Finishes on the interior had to be water resistent and food safe.

I have not been able to look at the bottom because it is so heavy....I do not see a stamp inside, unless stamp/sticker would be on the upper left(I think), as the lining is gone. The drip pan was rusted out even when mom was a kid. It has been a liquor cabinet for at least 60 years! And the last thirty rarely opened, as I/friends do not drink ETOH much....
Thank for hints-will look some more, although I think I looked everywhere over the years!

When pricing this, condition is a more important factor than the manufacturer. It's a great decorator piece and I think it would easily sell in the right market.