Nevada casinos earned $567m in June, a year-on-year decline of 46%.
Casinos reopened on 4 June following a two-and-a-half month shutdown.
Las Vegas Strip casinos fared worse than the rest of the state with a drop of 61%, while Clark County fell 51%.
Elsewhere in the state, the hit was more limited.
Carson Valley Area and Elko County saw a decline of just 2% from a year ago.
Table, counter and card games took in win of $173m, down 57%.
Slot machines earned casinos $394m for a drop of 38%.
Sportsbooks lost $483,000 on $78m of handle. Revenue dropped 103% while handle fell 76%.