Kachemak Bay State Park, State park in Kenai Peninsula, Alaska, US.

Kachemak Bay State Park covers about 400,000 acres (1,600 km²) of the Kenai Peninsula around Kachemak Bay, with rocky and sandy beaches, dense mountain forests, and glaciers and icefields at higher elevations. Its ranger station stands at Halibut Cove Lagoon, and most of the park has no road access.

Kachemak Bay State Park was the first state park legislatively designated in the Alaska State Parks system, and Kachemak Bay State Wilderness Park is the state's only legislatively designated wilderness park. The two together cover about 400,000 acres (1,600 km2) around Kachemak Bay. In the late 1990s spruce bark beetles infested the area, leaving thousands of acres of dead standing trees; the Mile 17 fire later burned dead spruce on park land.

The name Kachemak comes from the Aleut language and means "smoky bay". The park lies across the water from Homer, and the ranger station sits at Halibut Cove Lagoon, where boaters and fliers check in before heading into the backcountry.

The park is accessible only by water taxi departing from Homer, as no roads lead directly into the wilderness. Visitors should prepare for remote conditions and plan to hire local guides or boats for exploring the area.

The park's spruce forests were hit by bark beetles in the late 1990s, leaving thousands of acres of dead trees standing. The Mile 17 fire later burned areas of dead spruce on park land, and the Russian-language source dates a fire to 2009.