What great forest of Middle-Earth is Legolas from?

Legolas is from Mirkwood, the great forest of Middle-earth.

In Tolkien’s legendarium, Mirkwood lies in Rhovanion, east of the River Anduin. It was once called Greenwood the Great, but the forest became increasingly dark and dangerous after the Necromancer established the fortress of Dol Guldur nearby. The name Mirkwood reflects that corruption and the forest’s perilous reputation.

Legolas is the son of Thranduil, the Elvenking who rules the Woodland Realm in northern Mirkwood. Although Legolas joins the Fellowship of the Ring and spends much of the story outside his homeland, his woodland-Elf heritage explains his exceptional eyesight, agility, archery, and familiarity with forests.

Mirkwood is sometimes confused with Lothlórien or Fangorn. Lothlórien is Galadriel and Celeborn’s Elven realm, while Fangorn is the ancient forest associated with the Ents. Mirkwood is especially prominent in The Hobbit, where Bilbo and the dwarves cross it on their journey to Erebor.