Colorado has made more than $1bn (£789m) since it legalised marijuana in 2014, with more than 41,000 people now licensed to work in the industry.
It is the latest milestone for the state which has been home to more than $6.5bn in total cannabis sales since legalisation.
April, which includes the annual marijuana celebration 420, and May this year were the two highest-grossing months in the five-year history of the industry. Sales reached a peak of $24.2m in April, with May's figure being $23.9m.
Demand has been steadily growing, with the state's revenue growth from $500m to $1.02bn in just under two years - while getting to $500m took three-and-a-half.
In February 2014, the first month with sales data, the state's total tax and fee revenue was $3.5m. Since July 2017 that monthly figure has not dipped below $20m. Although that does include a rise in the sales tax on cannabis from 10 to 15 per cent that kicked in that month.