That's my mountain came from a battle between Adam and Liam about who had claimed Mt. Talbert as their mountain first. Mt. Talbert is a deciduous tree-covered hill that has been mostly untouched by real estate. A good view of it can be obtained from Timber Valley Drive. Adam claims that he used to look out his window and say "That's my mountain", but Liam claims to have done the same without ever knowing that Adam did so.
The mountain has a hidden trail that the boys have gone up numerous times.