The castle itself stands at the southwest corner of a rectangular bawn, or fortified courtyard, which is defended by towers at three of its four corners. The bawn walls, dating primarily from the 15th century, have been partially obscured and lowered over time to accommodate 18th and 19th century farm buildings, creating an intriguing blend of medieval military architecture and later agricultural structures.

The defensive walls tell a story of continuous adaptation and use. The southern wall, heavily reconstructed, now incorporates a 19th century farmhouse that serves as a coffee shop, built directly against its external face. The original entry to the bawn was through a rebuilt segmental arched gateway in this wall. Each corner tower had its own defensive purpose; the northeast tower contains a vaulted chamber lit by slit windows that were later partially blocked to create musket loops, whilst the northwest tower houses a chamber complete with a large garderobe. The western wall features two impressive double light pointed arch windows with widely splayed embrasures and window seats, suggesting this section may have served a more residential function.

Archaeological investigations have revealed an even older story beneath the current structures. Wall foundations of undressed masonry underlying the western bawn wall and northwest tower indicate the presence of an earlier structure, possibly a 13th or 14th century hall type building. Similar foundations have been uncovered near the northeast corner of the bawn. This evidence suggests that Barryscourt has been an important site for far longer than the standing remains indicate, with the northwest and southeast towers receiving further refurbishment in the 16th century. The castle complex has been under a preservation order since 1974, ensuring this remarkable survivor of medieval Ireland continues to tell its story to future generations.