The Nasu Kanga ruins (那須官衙遺跡, Nasu Kanga iseki) is an archaeological site with the ruins of a Heian period government administrative complex located in what is now part of the town of Nakagawa, Tochigi prefecture in the northern Kantō region of Japan.

Whereas as the governor (kokushi) was an official dispatched from the central government on temporary assignment, the district rulers (gunji) were typically hereditary local chieftains or nobility.

The ruins are located at the end of the Kitsuregawa hills on the left bank of the Bokigawa, a tributary of the Naka River.

Inside the enclosure, there were the elevated foundation bases of a large building and many warehouse structures, presumably for storing tax rice.

Artifacts found at the site are displayed at the adjacent Tochigi Prefectural Nasu Fudoki no Oka Museum.