Udon Thani provincial administration officials and Army troops raided a pub in Muang district early on Thursday and found 159 underage drinkers inside.
The raid against the Night Bar on the Thaharn Road in Tambon Mak Khaeng in Muang district was led by Udon Thani governor Pramote Thanyapuet at 1.30am.
The officials found that customers were still drinking and dancing after the 1am closing hour.
Authorities then checked customers' ID cards and found that two of them were under 15, three under 17 and 144 are between 18 and 19 years old.
Thani said the raid was conducted following complaints that the bar allowed teens under 20 inside.
He said the owner of the bar will be charged with violating the closing hour, selling alcoholic drinks after permitted hours, and allowing persons under 20 to go inside an entertainment place and selling alcoholic drinks to persons under 20.