Saṅghamittā is the eldest daughter of Emperor Ashoka and his first wife, Devi.

Together with Mahinda, her brother, she enteres an order of Buddhist monks.

The two siblings later go to Sri Lanka to spread the teachings of Buddha at the request of King Devanampiya Tissa (250 BCE– 210 BCE) who is a contemporary of Ashoka (304 BCE – 232 BCE).

At first she lands in 'Mathagal'.

The village Mathagal is situated sixteen kilometers away from Jaffna town, in the north of Sri Lanka, along the shores of the Indian Ocean.

Buddhist Emperor Samrat Ashoka sends her to Sri Lanka together with several other nuns to start the nun-lineage of Bhikkhunis (a fully ordained female Buddhist monastic) at the request of King Tissa to ordain queen Anulā and other women of Tissa's court at Anuradhapura who desire to be ordained as nuns after Mahindra converts them to Buddhism.

After Sanghamittā’s contribution to the propagation of Buddhism in Sri Lanka and her establishing the Bikhhunī Sangha or Meheini Sasna (Order of Nuns) there, her name becomes synonymous with "Buddhist Female Monastic Order of Theravāda Buddhism" that is established not only in Sri Lanka but also in Burma, China and Thailand, in particular.

The day the most revered tree, the Bodhi tree, a sapling of which is brought by her to Sri Lanka and planted in Anuradhapura, and which still survives, is also celebrated every year on the Full Moon day of December as "Uduvapa Poya" or "Uposatha Poya" and "Sanghamittā Day" by Theravāda Buddhists in Sri Lanka.