Thranduil of Mirkwood, was the last Elvenking to remain in Middle-earth at the end of the Third age. His realm was deep within the great forest of Mirkwood, largely hidden from the outside world. Although the Elvenking himself was Sinda, his subjects were the smaller Sylvan elves, whose natural home is the forest. His palace, comprising a magnificent cave system lay deep beneath the forest floor.

Although the Elvenking and his people had some commerce with the folk of Laketown, the contact was indirect, and the elves of Mirkwood shunned the outside world wherever possible. Critical events in the wider world, however, sometimes forced Thranduil’s people out of their forest fastness. Such an event was the upheaval caused at Laketown and beyond by the death of Smaug the worm. The Elvenking led out his army on this occasion to fight beside the Men of Laketown in the battle of the five armies.