Many questions can be answered by calling 1 (800) ASK-USPS (1 (800) 275-8777). 
Your local post office phone number is also available from this service.

Tenants Harbor Post Office
2 Main Street
Tenants Harbor, ME 04860

Port Clyde Post Office
860 Port Clyde Road
Port Clyde, ME 04855

Spruce Head Post Office
11 Post Office Road
Spruce Head, ME 04859