I've discussed before how the 1920 Maine Statehood Centennial Half Dollar was hoped - by the Maine Centennial Committee - to be available during the State's official celebrations in late June-early July 1920 but that it didn't happen because the coins weren't struck until late August 1920. (You can read the details here:
920 Maine Statehood Centennial - Late For The Show!.)
The "Official Program" for the Centennial included the Event Calendar for the celebration, listings of the members of the various Committees responsible for the staging of the scheduled celebrations and lots of additional information about the events and those who made them possible (beyond the Committees).
Maine Centennial 1820 1920 Official Program - Front Cover
Maine Centennial 1820 1920 Official Program - Events Page Sample
The Committee had its official Headquarters within the Portland, Maine City Hall. From this location, it offered visitors general Centennial information, answered questions, provided directions, etc. It also sold official Centennial souvenirs and books about Maine from the office.
Maine Centennial Committee Headquarters
(Image Credit: Maine Centennial 1820-1920 Official Program.) Proof of the Committee's expectation that it would have its commemorative coin available during the celebration is found in this brief item included in the "Official Program":
"The Maine Centennial half-dollar which is to be issued by the United States Government in commemoration of the event, also will be on sale at Centennial Headquarters."
Alas, it was not.
1920 Maine Statehood Centennial Half Dollar

For other of my posts about commemorative coins and medals, plus other stories about the Maine Centennial coins, see:
Commems Collection.