The Post also recorded 640 million page views.
Readers spent an average of 16 minutes consuming Post content, up 11 percent from June 2018.
Mobile mobile readership totaled 65.5 million, up 5 percent year over year.
The number of visitors grew by 3.5 percent compared to last year, according to comScore.
Mobile readership grew by six percent year-over-year.
The Post also recorded a total of 785 million pageviews.
Visitors spent more than 15 minutes on content, an increase over the previous month.
Pageviews were up 11 percent compared to December 2017.