Why is Songjiang called Rongcheng?

Rong is a deer, and Songjiang has fertile land in its early years, which is suitable for deer to thrive, so it has the reputation of "ten deer and nine heads back". So later people called Songjiang "Rongcheng". In addition, Songjiang is nicknamed "Cloud Room" and "Huating".

It is worth mentioning that Songjiang, formerly known as "Songjiang" (now Suzhou River), can cause large-scale disasters due to flooding. In order to ward off evil spirits and eliminate disasters, people changed the word "Song" to "Songjiang".

Other administrative units in Songjiang District also bear the imprint of water, such as Sijing and Dongjing.

Hehe, it seems that the answer is a bit off topic.