The Columbia River Treaty was signed by Canada and the US on 17 Jan 1961 after 15 years of preliminary investigation by the International Joint Commission, and one year (1960) of direct international negotiation. It dealt with the co-operative development of the Columbia River.

Canada undertook to construct 3 dams for water storage projects in the Canadian portion of the Columbia River basin and to operate them to produce maximum flood control and power downstream. In return, the US would pay Canada US$64.4 million (calculated to be half the worth, in 1961, of the flood protection the US would enjoy over the treaty's 60-year life); it would give Canada title to half the power produced; and would return this power to Canada. The treaty gave the US an option to build a trans-boundary project on the Kootenay River, and gave Canada the right at specified times to divert portions of the Kootenay's flow northward into the Columbia.

The treaty did not become effective until 16 September 1964, much of the delay resulting from a federal-provincial controversy over BC's 1961 decision to sell the power entitlement in the US. The province prevailed in January 1964, when the power benefit for the first 30 years was sold for a lump sum prepayment of US$254.4 million and the treaty was slightly modified by protocol. As the Canadian owner of the resource, BC was heavily involved in the negotiations, and in 1963 and 1964 it assumed Canada's obligations. Its agency, BC Hydro, has constructed all the Canadian treaty projects, and with an American counterpart co-ordinates their storage releases to the advantage of both countries. BC saw the return of downstream benefits beginning in 1998, when the first part of the sale ended. In November 1996 the Columbia Peace Treaty entities signed an agreement that these benefits will be returned to BC in the form of electricity. Fully 11/14ths of this electricity will be delivered to BC from Blaine and 3/14ths will be delivered from Nelway and Waneta.