https://www.siliconvalley.com/2020/06/26/h-1b-government-issues-first-ever-official-estimate-of-visa-population-in-u-s/

The federal government on Friday issued a first-ever official estimate of the number of people in the U.S. who hold the controversial H-1B work visa, intended for jobs requiring specialized skills but attacked by critics over reported abuses.

At the end of September, there were “approximately” 583,420 people on the H-1B living in the U.S, according to a U.S. Customs and Immigration report. The agency provided estimates going back the previous three years, but gave total numbers of people whose H-1B applications were approved, rather than the total it believes have been living in the country. The larger “approved” numbers don’t factor in withdrawals of approval or changes in visa status.