Leadbetter Point comprises the northern 6.8 kilometers of the Long Beach Peninsula at the mouth of Willapa Bay, and includes Grassy Island and surrounding mudflats. The northern two-thirds of the area is part of Willapa National Wildlife Refuge; the remainder is in Leadbetter Point State Park. The sandy tip of the point has been designated a Research Natural Area, with emphasis on the Snowy Plover.
Leadbetter Point consists of sandy ocean beach, sand dunes, intertidal mudflats, eelgrass beds, and salt marsh. The upland areas of the point contain a diverse forest dominated by Sitka spruce, western hemlock, and red alder, with an understory of willow, cascara, and western crabapple. This IBA supports regular large concentrations of waterfowl, including Brant and shorebirds. The ocean beach is a documented active breeding site for Snowy Plover, and has been proposed as critical habitat by for this species by the U.S. Fish and Wildlife Service. Spring shorebird counts typically exceed 10,000 individuals. It is estimated that Leadbetter Point hosts about seven percent of the Willapa Bay shorebirds in spring. When Sand Island is submerged by tides (see Sand and Gunpowder Islands IBA), Leadbetter Point is a secondary roost site for Brown Pelicans. Over 180 bird species have been recorded here. This area is considered an important staging site for passerines in spring migration.
Disturbance from recreational use is the single most serious threat to nesting Snowy Plovers. Wetland areas are vulnerable to invasion by non-native plants, particularly the cordgrass Spartina.