Ashok Vatika was a garden in Lanka that was located in the kingdom of the Rakshasa king Ravana, as mentioned in the Vishnu Purana and the Hindu epic Ramayana of Valmiki, and all subsequent versions, including the Ramacharitamanas written by Tulsidas, where it finds mention in the Sundar Kand.The Vatika has garden houses around it, built by Vishwakarma himself.
It was the location where Sita, the wife of Rama, was held captive by Ravana after her abduction, also because she refused to stay in Ravana's palace and preferred to stay under the Ashoka tree, hence the name. It was here that Ravana's wife Mandodari came to meet her and also where Hanuman met her for the first time, and identified himself with the finger ring of Rama.
Ashoka tree (Saraca asoca), often known as Sita-Ashok owing to its connection with the Ramayana
Sita stayed at Ashokat Vatika until the end of the epic battle between Rama and Ravana, which resulted in the destruction of Ravana himself and most of this clan. Much of the Ashoka Vatika was destroyed by Hanuman when he first visited Lanka searching for Sita. Also destroyed was the Pramda Van at the centre of the Ashok Vatika.