Twenty-four secondary stupas from the Davaravadee period dating back about 1,300 years have been found near the historic monument of Khao Khlang |Nok in Si Thep district, Phetchabun.
Phongthan Sampao-ngern, chief ranger at Si Thep Historical Park, said yesterday that each stupa was eight metres long and eight metres wide.
A wheel of Dhamma made of laterite was also found.
It is thought the stupas were built during the 13th and 14th century of the Buddhist era.
The excavation of the site started early this year after the main stupa was found.
The Historic Park was built around 1,300 years ago for the purpose of conducting Buddhist and Brahman religious ceremonies.
The site is considered to be the most complete one in Thailand.