Maine resident enlisted service members on active duty can get a free day-use pass to state parks and historic sites. It admits you free, and admits your spouse and children free when they are with you.
Call 888-365-9287 or email the Maine National Guard Soldier and Family Readiness Office at ng.me.mearng.list.me-mil-fac@army.mil to request an application.
Proof of active duty service, such as a statement of service from your commanding officer or your military ID card, plus proof of Maine residency.