The state was also amongst the first to legalize bingo in the states (in 1952), although it should be noted that this discipline faces a number of restrictions and can only be conducted by charitable organizations.ġ972 A state lottery in Maryland was fully legalized in 1972, and this remains available to all state residents aged 18 or over. 1920 Maryland has always been synonymous with pari-mutuel horse racing wagering, with this practice having been regulated way back in 1870 and formally legalized in 1920.