Governor Thanakorn Ungchitpaisarn explained that the province has several rivers which are attractions for both locals and tourists.
The infection risk had been heightened by the return of many Uttaradit residents from other provinces that had been hit harder by Covid-19, he added.
To prevent a rise in cases, people would not be allowed to gather at tourist attractions, he said. Anyone who violates the rule will faces up to a year in prison and/or a fine of Bt100,000.
Uttaradit has recorded no new cases of Covid-19 for the past month, but the northern province upped monitoring efforts after the recent return of 73 residents from virus hot spot Phuket.