Battle of Plum Creek
1840 CE.
Shown on the map at 29.884°, -97.668°.
The Battle of Plum Creek was a clash between allied Tonkawa, militia, and Rangers of the Republic of Texas and a huge Comanche war party under Chief Buffalo Hump, which took place along Plum Creek near Lockhart, Texas, on August 12, 1840, following the Great Raid of 1840 as that Comanche war party then returned to west Texas.
Text from the Wikipedia article Battle of Plum Creek, licensed CC BY-SA 4.0.