Danyang is a county-level city located on the southwest (right) bank of the Yangtze River, and is under the administration of Zhenjiang, Jiangsu province, China. It is noted for the production of optical lenses used in sunglasses and eyeglasses. Danyang has a total area of 1,059 km2 (409 sq mi) and a population of roughly 890,000. Danyang locals speak a dialect of Wu Chinese, and the city is on the linguistic borderline between Wu Chinese and Jianghuai Mandarin.

Zhenjiang, alternately romanized as Chinkiang, is a prefecture-level city in Jiangsu Province, China. It lies on the southern bank of the Yangtze River near its intersection with the Grand Canal. It is opposite Yangzhou and between Nanjing and Changzhou. Zhenjiang was formerly the provincial capital of Jiangsu and remains as an important transportation hub. As of the 2020 census, its total population was 3,210,418 inhabitants whom 1,266,790 lived in the built-up area made of the 3 urban districts. The town is best known both in China and abroad for Chinkiang vinegar, a fragrant black vinegar that is a staple of Chinese cooking.