to further what /u/Guygan said, here is an online map of many/most of the parcels in maine. it can be a bit arcane, translating the locality tax map number and parcel number into the number used by the statewide parcel viewer, but it's usually relatively straightforward once you figure out the typical patterns they follow.

for many of the towns/territories that are not on the above map, googling '<TownName> tax map' will lead you to pdfs of the tax maps.

there are some localities where tax maps are not available via either of the 2 methods above, but they are pretty rare in my limited experience.