This is a type of beetle in the scarab family, of which many species occur in Maryland. Within that group, only a small handful of species cause damage to garden plants, and even then, their damage tends to be minimal, especially as adults. Some species feed on turfgrass roots or other plant roots as juveniles (grubs/larvae), though not all. Adults are often generalists, chewing on foliage of a variety of plants, usually at night.

Since they are often night-flying, adults can be drawn to outdoor sources of light like porch lights, garage lights, lamp posts, and any landscape accent lighting. Turning them off might keep abundant numbers of these beetles from congregating in the yard, especially since some use an aggregation pheromone to draw-in other members of their species for either mating or group feeding.

It's hard to tell which species this is in the photos, since several scarabs have this general body shape and coloration. One of the "chafer" species or the Asiatic Garden Beetle is a possibility. Since their life cycles differ, control would depend on which species they belong to. Adult beetle size might narrow it down slightly, but not enough to tell which exact species this is. Fortunately, that shouldn't matter too much, as unless you have noticed significant plant damage associated with their feeding, no action needs to be taken. (If there is extensive plant damage, please share photos so we can make recommendations.) No pesticide use is recommended, and several kinds of beneficial insects (as well as birds and possibly also bats overnight, pursing any flying adults) will prey on the beetles and help reduce their numbers naturally.

Miri