Illefarn was an ancient elven city-state that was founded over 23,000 years ago. It grew into an expansive nation and later fragmented into smaller realms.
Illefarn as a nation at its height stretched along the Sword Coast from just south of modern day Luskan, to around the town of Daggerford. Its capital was Aelinthaldaar which was built in the shadow of Mount Waterdeep.
The nation's population dwindled as it's elven citizens broke off into smaller kingdoms. These kingdoms would eventually deteriorate after a massive horde of orcs invaded the Sword Coast 1500 years ago.