Nong Bua Lamphu Province จังหวัดหนองบัวลำภู is a province of the Northeastern Region of Thailand in the heart of the Khorat Plateau. It covers 3,859 sq km (1,490 sq mi) and has a population of 503,000 people (2012 estimate). It ranks 55th in size, 51st in population, and 33rd in population density among the 76 provinces of the kingdom.
Nong Bua Lamphu Province is bordered by Udon Thai Province to the east, Khon Kaen Province to the south and Loei Province to the west. It comprises 6 districts (amphoe), namely Mueang Nongbua Lamphu (provincial capital), Na Klang, Non Sang, Si Bun Rueang, Suwannakhuha and Na Wang. The districts are subdivided into 59 subdistricts or tambon, and 636 villages or muban.
Nong Bua Lamphu has been inhabited for centuries. It was under the rule of the Lan Xang Kingdom until the Siamese took over control of the province in the 19th century. It was originally part of Udon Thani province, but was separated out in 1993, becoming one of the three youngest provinces of Thailand, along with Amnat Charoen Province and Sa Kaeo Province.