The Grand River land dispute, also known as the Caledonia land dispute, is an ongoing dispute between the Six Nations of the Grand River and the Government of Canada. It is focussed on lands along the length of the Grand River in Ontario known as the Haldimand Tract, an 385,000 hectares (950,000 acres) tract that was granted to Indigenous allies of the British Crown in 1784 to make up for territorial losses suffered as a result of the American Revolutionary War and the Treaty of Paris (1783). The Six Nations were granted the land in perpetuity and allege that lands were improperly sold, leased or given away by various Canadian governments, leaving only 5 per cent of the original lands under Six Nations control. The Six Nations also allege that monies owed to the Six Nations from leases and loans on much of the tract have not been paid or were redirected into government coffers.

The dispute has been the subject of many formal negotiations under the land claims process since the 1970s and several instances of direct action in the form of protests, blockades, and occupations. Formal negotiations have broken down, and the dispute is before the courts. The Government of Canada's policy to extinguish aboriginal title as a condition of settlement is considered unacceptable by the Six Nations. The Six Nations are seeking monies owing and ongoing payments for leased lands and the return of lands improperly transferred.

The dispute came to wide attention in Canada in 2006 when the Six Nations formally reactivated litigation initially brought in 1995 against Canada and Ontario. Protesters from the Six Nations of the Grand River demonstrated on a parcel of land in Caledonia, a community within the municipality of Haldimand County, roughly 20 kilometres (12 miles) southwest of Hamilton. Soon after this demonstration, the demonstrators took control of the disputed land, the planned site of a subdivision known as "Douglas Creek Estates". The land, along with all of Caledonia, is part of the "Haldimand Tract". The Government of Ontario compensated the developer and stopped the development, holding the land for planned negotiations.

In February and March 2020, the dispute once again entered public consciousness with Mohawk protesters blockading Highway 6 as part of the 2020 Canadian pipeline and railway protests in solidarity with the Wetʼsuwetʼen, and later with the occupation of the site of another planned subdivision in Caledonia, "McKenzie Meadows". The protestors have called the area "1492 Land Back Lane". Calling themselves "land defenders", the protestors have refused to leave despite being ordered to by an Ontario court.