Kejimkujik National Park consists of two parts: the main section of the park, located in the uplands of south-central Nova Scotia, and the seaside adjunct, located nearby on the Atlantic coast. The park covers an area of 381 km².

The main section of the park is a forested upland plain that contains many lakes and rivers. These interior waterways were important canoe routes between the Bay of Fundy and the Atlantic for the ancestors of the Mi'kmaq. The park also contains the petroglyphs that these people left behind.

The seaside adjunct includes white sandy beaches and coastal wetland areas. The park includes habitat for the endangered Piping Plover and other coastal birds.

The park is named after Kejimkujik Lake the largest lake inside the park. The lake's Mi'kmaq name has been translated as "attempting to escape" or "swollen waters", possibly related to fishing weirs placed on the lake.

Rivers in the park include the:

• Mersey River
• West River
• Little River