The Semidi Wilderness now contains a total of 250,000 acres and is managed by the Fish & Wildlife Service's Alaska Maritime National Wildlife Refuge. All of the Wilderness is in the state of Alaska. In 1980 the Semidi Wilderness became part of the now over 110 million acre National Wilderness Preservation System.

Nine major treeless and ragged rock islands, some sided with precipitous cliffs, were combined with many small rocks and islets to form Semidi Islands National Wildlife Refuge in 1932. In 1980 these lands became a subunit of the 715,000-acre Alaska Peninsula Unit of the Alaska Maritime National Wildlife Refuge and a Wilderness area. More than 2.4 million birds, almost half the breeding seabirds of the Alaska Peninsula Unit, nest on the Semidis. Aghiluk Island alone, the largest of the Semidis, is home to more than half a million birds. About 370,000 horned puffins nest in the Semidis along with almost all of the unit's northern fulmars and jaegers, and one million-plus murres. Ancient murrelets and parakeet auklets are among the other species found here. Seabird populations would be even higher, but fox farmers in the 1880s released their animals on some of the larger Semidis, and their descendants consume many eggs and birds annually.

Semidi Islands Wilderness Area is not great in land mass but includes approximately one-quarter million acres of surrounding seabed, providing at least temporary homes for sea otters, sea lions, seals, porpoises, and whales. Exposed to the stormy Gulf of Alaska, drenched by frequent rains, remote and difficult to reach, lying in poorly charted waters, this region is seen by few humans. The dangerous crossing of an unpredictable stretch of sea is simply too great a risk for most.

A journey to the far-flung islands of the Semidi Wilderness within the Alaska Maritime Refuge almost always involves a boat. Tour boats, ferries, planes , cruise ships or your own boat can transport you to parts of the refuge. No refuge lands are accessible from the road system. Homer and Seward are the only road accessible communities near the refuge. All other communities in and near the refuge are accessible by scheduled air service and some such as Sitka, Seldovia, Kodiak, Chignik, Sand Point, King Cove, Cold Bay, False Pass, Akutan and Unalaska also have ferry service. For those not ready to set sail, the Alaska Islands & Ocean Visitor Center and Refuge headquarter at 95 Sterling Highway # 1, Homer, Alaska, can be reached by vehicle and scheduled aircraft from Anchorage (225 miles).