Petit Manan NWR has a surface area of 6,367 acres (25.77 km2).[2] It is part of the town of Steuben.
The refuge has four mainland divisions. The 2,195-acre (8.88 km2) Petit Manan Point Division. The Gouldsboro Bay Division protects 623 acres (2.52 km2). The 1,028-acre (4.16 km2) Sawyer's Marsh Division. The 431-acre (1.74 km2) Corea Heath Division.
Petit Manan NWR includes 2,078 acres (8.41 km2) acres on 41 islands, stretching the entire coastline of Maine.