There are approximately 328.2 million people in the US.— Kyle Feldscher (@Kyle_Feldscher) September 16, 2020
To get to the low end of herd immunity, about 60% of the population must catch Covid.
That's about 196,920,000 cases.
The current US death rate is about 2.96%.
So that's 5,836,679 deaths necessary for herd immunity.