Wat Siri Chanthara Nimit Worawihan, also known as Wat Khao Phra Ngam, is located in Khao Phra Ngam Subdistrict. Originally an abandoned temple, its founding date remains uncertain. In 1912, Phra Ubali Khunupamachan (Chan Sirichantho), an abbot of Wat Borom Niwat in Bangkok and another monk conducted an ascetic practice here. Impressed by the landscape, they decided to erect a Buddha image on this hill. The image has a lap width of 22 metres and measures 36 metres high from its lap to the top of the head, with the image’s hair curls made from garlic earthen jars. Upon completion, it was named "Phra Phuttha Naruemit Matthayom Phutthakan" and later renamed "Phra Phuttha Patiphak Matthayom Phutthakan (Luang Pho Yai)" in 1926, a name it retains to this day.

Inside the temple, you'll find a reclining Buddha image made of ancient laterite, believed to have been built around 557. Additionally, significant relics like replicas of the Buddha's footprints, cast in cement, are situated near Phra Phuttha Patiphak Matthayom Phutthakan (Luang Pho Yai).