Battle of Yan Province
194 CE.
Shown on the map at 34.089°, 113.669°.
The Battle of Yan Province was fought between the warlords Cao Cao and Lü Bu for control of Yan Province (covering present-day southwestern Shandong and eastern Henan) in the late Eastern Han dynasty. The battle lasted for at least one hundred days with an indecisive conclusion.
Text from the Wikipedia article Battle of Yan Province, licensed CC BY-SA 4.0.