AUGUSTA — Maine motorists with vanity license plates that support conservation are getting one final chance to visit state parks free of charge.

Sunday is the second and final day of free admission to 48 state parks and historic sites to vehicles bearing “loon” license plates

Open admission applies to all sites except for Baxter State Park and the Penobscot Narrows Observatory in Prospect.

More than $17.5 million in proceeds have gone to support conservation and wildlife efforts since the plates became available in 1993.