Stamp Giveaway # 33 (R. Hill anniv.) [solved]

Solomon Islands souvenir sheet; Comoro Islands set and souvenir sheet, gold foil single and souvenir sheet; Guinea-Bissau set and souvenir sheet

Only question: What was the last foreign post office in Hamburg to close after the Free City became part of the North German Confederation?

Winner will provide the correct answer before or at 10 A.M., Sept. 13, 2021, eastern US time. If there is no correct answer, the first response will win. My decision as to winner will be final.

Good luck to all who choose to participate!

Will

Just a wild guess..Austrian Empire?

I made a small research.
But given that Hamburg joined the German-Austrian Postal Union from 1852 to 1866, and that Hamburg joined the North German Confederation in 1866, I believe that allexis is right, the answer is Austrian Empire.
But I want to add as fun fact that before the postal union with Austria there were other foreign post offices in the city: swedish-norwegian, danish and other german city-states.

I can't find anything about an Austrian post office in Hamburg.
I believe it is Sweden. The North German Confederation closed all foreign post services on March 31st 1869. The Danish post office got closed in April 1868.

MS2007 wins! The Swedish post office was the last to close in Hamburg.

Your stamps will be on the way shortly. I hope you like them.

Watch for the next giveaway. All are welcome to participate.

Will

Awesome thanks!