With my figures taken from the ever reliable World-O-Meters web site
IF America carries on at approximately its current daily death rate then they'll top the 600,000 total in less than 20 days - this is a big mile stone
The next mile stone that I really, really hope doesn't (but fear it will) get broken is the 666,441 - this is the total combat deaths of every American soldier in every conflict . . . like, ever. From the American Revolution war right through to the 2017 death of some poor sod during a Raid on Yeman
And the final mile stone that would be a disaster if they broke would be 675,000 (ish) or the death total from the 1918 Spanish Flu