The Fairchild manor is the home of the Fairchild family in Idris.
After the Uprising, Valentine burned the house down with Jocelyn's parents in it, along with Michael Wayland and his son to fake both his and Jonathan's deaths, and also Aurora Fairchild in it.
The ruins of the manor have since been left in a charred state. Apparently, no one wanted to take the land, or build anything on it as they think the place is cursed, given the horror Valentine has unleashed there.
In season 3 Aurora goes to visit the manor along with Jace, Isabelle and Alec.