When compared to their peers, both islands are relatively low-lying limestone formations.
The highest point is located in the hilly region of southwestern Antigua, as there, Mount Obama (formerly Boggy Peak), the remnant of a volcanic crater rises to 399 m (1309 ft).
Barbuda's highest elevation is 44.5 m (146 ft), a part of the highland plateau on the eastern edge of the island.
Both islands are ringed by reefs and sandbars, and indented by beaches, small lagoons, and natural harbors.
There are no rivers of note and only a few streams, as rainfall amounts are quite light. The most noteworthy landform of Barbuda's coastline is the Codrington Bay natural lagoon on the western side of the island.