The Hastings' Cabin

Also known as "the lake house."

The precise location of the Hastings' Cabin is unclear, but it does not seem to be in Rosewood proper.

In Season 1, " A " is seen burning the tree trunk bearing the " Alison + Ian " inscription. There is speculation that the trunk was burned in the hearth of the Hastings' private cabin.

In "Save the Date," Hanna takes Caleb to the cabin without Spencer's family's permission; she seeks a secluded spot where Caleb's stalker won't be able to find them. While there, they remove the covers protecting the furniture and ignite the fireplace. It is later revealed that Hanna took Caleb here without Spencer's permission or knowledge.

In A Hot Piece of A, Hanna throws Caleb a surprise party at the lake house.

Book Series
In the books, Spencer's family's cabin is where Alison is said to have died in a fire. Alison and the Pretty Little Liars had gone there when Alison confessed to having a doppelgänger. Alison had then sent fire to the house while the girls were inside, but they had managed to escape, including perhaps Alison.