More than 6.8 million people are known to have been infected in the US, more than in any other country.
The milestone comes amid an increase in cases in a number of states, including North Dakota and Utah.
President Donald Trump said on Tuesday the new death toll was a "horrible thing" and claimed China "should have stopped" the virus.
He also defended his record, claiming that had the US not taken action, "you could have two million, 2.5 or three million" dead.
JHU reported the new death toll of 200,005 on Tuesday. The university has been collecting US and global coronavirus data since the outbreak began late last year in China. The first case in the US was confirmed in January.