The catholic mission of Sangsay is situated 14 kms away from Kalimpong. Fr Gaston Grutuz, a French father was the first one to visit this place. The Lepcha people of this area welcomed him. He felt the need of education in the village, and he recruited John Lepcha as a teacher for the area. The school began to flourish. Swiss fathers from Pedong mission used to visit Sangsay and looked after the educational needs of this village.
In 1952, Fr Gex Collet and Sr Anne Mary, a nurse used to go to Sangasy to take care and look after the sick. The first five Catholic families attended Sunday Mass at Mirik near Algarah.
Fr Pillet, helped the local people to construct a small chapel in a land donated by the villagers themselves. Fr Marian with the help of Seva Kendra, Siliguri, made approach road connecting presbytery to main road. Fr. John Lorendo helped solve the water scarcity of village by making arrangements to get water from reservoir to Sangsay village.
The Sisters of Charity of Nazareth came to Sangsay in 1986. Now, the Sisters of Charity of Nazareth look after St. Dominic Primary School and a dispensary called Nazareth Lee Centre. The Sangsay Catholic mission is looked after by the Roman Catholic Diocese of Darjeeling.