Dinh Trang site in the Red River civilization ; ; The Dinh Trang site is named Dinh Trang village, distributed on a high mound next to the ancient Hoang Giang river, located adjacent to the northeast of Co Loa citadel – the capital of the Au Lac state during the An Duong King. The relic was discovered in 1969 and has been excavated with an area of nearly 800m2. The cultural layer of the site is 2m thick, preserving the vestiges of 4 layers of continuously developing culture, from Phung Nguyen – Dong Dau – Go Mun to Dong Son