Most states don't even know how many they have or what they're for.
"…over the past century, many markers have also become symbols of the country's dark and complicated past, in some cases erected not to commemorate history but to manipulate how it is told, NPR found.
From the Atlantic through the Plains, more than 270 markers describe Native Americans as "savage," "hostile" or "semi-civilized," or they use racial slurs.
In the West and Southwest, markers herald the work of missionaries and praise rangers without mentioning the violence and cultural destruction they often inflicted.
Across the South, markers honor notable men and notable houses without mentioning the forced, free labor that made both the homes and the men's wealth possible. NPR found that nearly 70% of markers that mention plantations do not mention slavery."
https://www.npr.org/2024/04/21/1244899635/civil-war-confederate-statue-markers-sign-history has more context and stories most people probably don't know. I wish they had more blatantly mentioned how Emmett Till's marker is frequently shot up by racists. However, I didn't know the specifics about the U.S. war against the Dakota.