I've got the box as 9 x 12 x 2; but I've got a big deck together in a ziploc keeping mine from closing flush - not necessarily a bad thing. Anyway, my copy is 2 and a eighth thick, actually.
Perfect, thank you! Amazon has it listed at 3 inches thick which was surprising since BGG has it listed at 2.2 inches. I just wanted to check since BGG has 1846 from the same company as 2.2 inches and it's actually a little over 3 inches thick so I wanted to check.