Dirty little secret, the klan was also very active up north. When I grew up in Monsey, NY (25 mi NW of NYC) a few miles down the road was a dilapidated old building alongside one of the old Eire Lackawanna RR tracks that was used as a meeting house for the local klan chapter many years earlier. And yes, they would march in Memorial Day and 4th of July parades waving the Stars and Stripes.
The most widespread Klan ever in early 1900s was mostly a northern thing
Three klans pretty much
The Reconstruction era klan we can argue to pieces here and do
Thaddeus and Sumner versus Forrest and Wheeler pick yer favorites
Then the early 1900s anti black anti Catholic anti immigrant klan which was mostly a Yankee klan
Then lastly the segregation era Klan which reached its zenith killing civil rights activists and intimidating voting rights movements which was mostly a Southern klan
Today the Klan is insignificant but those who do it are pretty much Midwestern and mid south and a few Deep South
I could be wrong but they exist mostly in the minds of the paranoid and Hollywood today
Even in my youth in Mississippi b1957 they were much stronger but still eschewed by reasonable folks as tacky at best
The middle klan was the high water mark
Oxford is a lost cause for now not worth fretting over