The association spans the area from the Clarence River in the north to the Rakaia River in the south and from the Southern Alps in the west to the Pacific Ocean in the east excluding metropolitan Christchurch which is defined as follows:
The area bounded by the Waimakariri River in the north, from the Waimakariri River across the Old West Coast Road, along Miners Road and Church Road, through Templeton, along Trents Road to Blakes Road, along Blakes Road to Springs Road (excluding Prebbleton township) along Springs Road to Halswell Junction Road to Halswell (including Halswell township) from Halswell in a direct line to the sea at Governors Bay (excluding the Governors Bay township), and following the coastline north to the Waimakariri River. ("the area")
