The Silvan Elves or Wood-Elves were those Elves who remainds in the woodlands of Rhovanion, either in Greenwood or Lorinand, rather than go to Valinor or even Beleriand. Some of the Silvan Elves did eventually arrive to Beleriand, but at a much later time than their brethern the Sindar. Having not been exposed to the divine influence of the Valar, they were deemed "less wise and more dangerous."
At the end of the First Age, Noldor (High Elves) from Valinor and Sindar (Middle Elves) from Beleriand arrived east, making contact with the Woodland Elves. Some of these Elves, namely Galadriel, Celeborn and Oropher, would become the lords of the Silvan Elves: Oropher (and his son Thranduil after him) in Greenwood, while Galadriel and Celeborn ruled Lorinand.
Due to their lesser status as subjects of their Noldor and Sindar rulers, few individual Woodland Elves have had a notable role in the history of Middle Earth or the course of the War of the Ring. One major exception is Tauriel, a Silvan orphan who was raised by Thranduil.
During the War of the Ring, Frodo and Sam see Wood Elves leaving Middle Earth for the Grey Havens.