Mirkwood was a large forest of Rhovanion, flanked by two great rivers, the north was bordering the Grey Mountains and the south by plains and wasteland. It is intersected by numerous rivers, notably the Forest River which flowed through the Elvenking’s land. This river had a smaller river branching off of it, which was enchanted and caused drowsiness and hallucinations. The forest was split by the Old Forest Road, a major trade route that connected the East and the West. Built by the dwarves to connect Erebor and the Iron Hills to the Misty Mountains in the 2nd Age but fell into disuse when the dwarf kingdoms fell. South of the Old Forest Road was much darker as the Elves had less control of the region. By the Third Age there were large spiders throughout the area drawn by the evil of Dol Guldur. Dol Guldur was a base used by Sauron as he regained his power, under the moniker of the Necromancer. The Silvan elves settled in Mirkwood (Greenwood The Great) on their journey to go West. They were less wise and reserved then other elves, and often celebrated with wine and feasts. The first king was Oropher, a grey elf who ruled until he died during the Battle of Dagorlad, slain disobeying orders. His son, Thranduil, became the king. By the Third Age the kingdom was in decline and it became Mirkwood. Thorin’s Company passed through Mirkwood on their quest to Erebor. They suffered passing the Enchanted River and attempted to hunt, but failed. They engaged with many of the Great Spiders and were almost defeated. Tired, hungry, and feeling the effects of the Enchanted River they were gladly captured by the Elves. They were detained by the Elvenking but thanks to Bilbo’s ring and cunning they escaped using wine barrels down the Forest River. During the War Of The Ring Mirkwood was attacked by Mordor, and in the Battle Under The Trees Thranduil repelled the attacks and Galadriel destroyed Dol Guldur. The forest was cleansed and Galadriel renamed it Eryn Lasgalen, “Wood of Greenleaves”. Notable people who dwelt in Mirkwood include Legolas, Radagast, and groups of Northmen.
“There are no safe paths in this part of the world. Remember you are over the Edge of the Wild now, and in for all sorts of fun wherever you go. Before you could get round Mirkwood in the North you would be right among the slopes of the Grey Mountains, and they are simply stiff with goblins, hobgoblins, and orcs of the worst description. Before you could get round it in the South, you would get into the land of the Necromancer, and even you, Bilbo, won’t need me to tell you tales of that black sorcerer.” - Gandalf’s warning to the Company of Thorin, The Hobbit, Queer Lodgings.