Coalgate is a locality in the Selwyn District of the Canterbury region of New Zealand's South Island. The 2001 New Zealand Census of Population and Dwellings gave Coalgate's population as 276, and it is located roughly an hour west of Christchurch on State Highway 77. The town's name stems from it being the "gateway" to the lignite coal fields around Whitecliffs, the Rakaia Gorge, and Acheron River.