The Unites States Fish and Wildlife Service manages this 2,750 acre National Wildlife Refuge as a wildlife habitat, with an emphasis on migratory birds. North and South Monomoy Islands are 2 barrier islands covered in beaches, salt and freshwater marshes, sand dunes and ponds. Headquarters and a nature trail are located on Morris Island, the only part of the Refuge accessible by car. The Refuge is home to large numbers of migrating shorebirds, waterfowl and songbirds. Thousands of endangered roseate terns use the refuge to stage for their long southern migration; the piping plover nests on the sandy beaches. Harbor seals winter by the thousands at Monomoy.

In the past 50 years Monomoy has been a peninsula, then an island, and now 2 islands. The force of the ocean continues to reshape the islands' contours by transferring sand from one spot to another. Nature's constant change is at work.

• Hike the nature trail on Morris Island and discover the transitional ecosystems from beaches to dunes to salt marshes to mudflats.
• Ride a ferry to South Monomoy Island and admire the weather-worn lighthouse.