The Darkening of Mirkwood is a campaign sourcebook for The One Ring: Adventures over the Edge of the Wild, the roleplaying game based on The Hobbit and The Lord of the Rings, by JRR Tolkien.

The Shadow falls once more on Mirkwood, shattering the short-lived optimism of the forest's inhabitants and neighbours, and endangering all those within reach of Dol Guldur's clawed grasp.