Salvatore Estate was a place where Stefan, Damon, Giuseppe Salvatore had lived 50 years before the Salvatore Boarding House was built. Katerina Petrova, the vampire that turned and created the bloodline of Stefan and Damon came here to live in 1864 with her handmaid Emily Bennett, being a powerful witch. The Salvatore Estate was destroyed after or during the Battle of Willow Creek.
Stefan tells Elena how he and Damon were both born and grew up there.
In the present day there are only ruins left located somewhere in the woods. Stefan hides Damon's ring here, after he had locked him in the Salvatore Boarding House basement. After Elena Gilbert discovered Stefan is a vampire, he took her to the ruins, explaining that, these ruins weren't just plain old ruins they had been his home sometime in 1864 by telling her that "This used to be my home".