The Matanikau River of Guadalcanal, Solomon Islands, is located in the northwest part of the island. During the World War II Guadalcanal campaign, several significant engagements occurred between United States and Japanese forces near the river.

Guadalcanal is the principal island in Guadalcanal Province of Solomon Islands, located in the southwestern Pacific Ocean, northeast of Australia. It is the largest island in the Solomons by area and the second-largest by population. The island is mainly covered in dense tropical rainforest and has a mountainous hinterland.