There are several dozen ant species in Maryland, and it can take microscopic examination to identify them to species. Indoors, large ants tend to be Carpenter Ants, which nest in wood which has usually been first compromised by exposure to moisture (like from a leak). The exact species of ant present may not matter too much when it comes to baits, as it can be difficult to predict which type of bait worker ants will find attractive at any given time during the colony's life. Baits can be based on sugar, fat, and/or protein. Only the wingless workers will be drawn to bait, since they are foraging for food to share with the colony; reproductive caste members (those with wings) are not foraging and are unlikely to visit bait stations (even if they did, they are only feeding themselves at that point, not bringing food back to the nest). You may want to work with a pest control professional if bait stations don't work to kill off the colony (which might take several rounds of trial-and-error to see what they will feed on), so an inspector can try to locate the nest.

Miri