Revenue at all three casinos declined from the same time last year.
MGM Grand Detroit dipped 1.7% to USD 49.6M, MotorCity Casino Hotel fell a half percent to USD 42.1M and Greektown Casino-Hotel dropped 0.9% to USD 29.3M.
MGM Grand had 41 percent of the month's market share, MotorCity had 35 percent and Greektown had 24 percent.
The casinos reported paying USD 14.4M in wagering taxes and development agreements to the city of Detroit in April, as well as USD 9.8M in gaming taxes to the state during the month compared to USD 9.9M last year.