The largest mass lynching in the United States was of 11 Italians in New Orleans:
And just for spice, so we remember this stuff is in living memory: https://en.wikipedia.org/wiki/Greensboro_massacre
https://en.wikipedia.org/wiki/Tulsa_race_riot
Technically not a lynching I suppose, but as far as mass killings of minorities go..
In any case, it just goes to show that many groups have been 'the other' that people blame for problems.
They were, of course, guilty — as their lawyer later told Upton Sinclair.