Map:Peninsula Map (Atlas of Worlds)
Connected patches of land using act2 grasslands tilests and having a generally unremarkable layout. The boss is a giant shambling rockpile enemy with additional life and the allies can't die aura. He has some backup, so approach carefully. You'll find him on a spit of land entirely behind a ruin wall with some backup, so be careful. Be aware, though it doesn't look like he should be able to, he can walk through the gate in said wall.
Vendor Recipe: Selling 3 dry peninsula maps (lvl 60) yields 1 thicket map (lvl 61)