3022.… are on display, fanned out in this picture:
The oldest one, in the upper-left-hand corner, which has the words GUIDE MAP visible, is from 1928. The one in front, red with the word SHELL on it in stacked type, is from 1939. I've collected them over the years from a variety of sources.
I'm thinking of going through them, one-by-one, and commenting on the interesting bits of each one. I already have some commentary on the 1928 map (complete with pictures) which can be read and seen.
They are, of course, amongst my proudest and most dear possessions, this collection. They tell an interesting story of Portland's growth.