The Township of Alnwick/Haldimand is a township in central Ontario, Canada, in Northumberland County, situated between Lake Ontario and Rice Lake. It was formed in 2001 by the merger of Alnwick Township in the north and Haldimand Township in the south. Alderville First Nation is an autonomously governed First Nation contained within the township boundaries, in two non-contiguous sections along County Roads 45 and 18.

Northumberland County is an upper-tier municipality situated on the north shore of Lake Ontario, east of Toronto in Central Ontario. The Northumberland County headquarters are located in Cobourg.