The two provinces, along with five First Nations, finalized their submission package Wednesday — the last step in what has cost millions of dollars and brought political heat for Manitoba Premier Greg Selinger.
"The UNESCO designation is really a world-class recognition of the southern boreal landscape that we are protecting," Selinger said.
"We're going to be globally recognized for what we've done to protect this site and it will attract eco-tourists from all around the world."
The 33,400-square-kilometre area is known as Pimachiowin Aki — an Ojibwa phrase that translates as "the land that gives life" — and is the last intact boreal forest of its kind in the world, Selinger said.
As part of the effort to protect the area, the provincial government in 2007 prevented Manitoba Hydro from building a transmission line through it. The government ordered the Crown utility to build a much longer line around lakes Winnipeg and Manitoba, which will cost at least several hundred million dollars more.
The Opposition Progressive Conservatives denounced the move as costly and unnecessary. They have repeatedly said construction of a transmission line wouldn't hurt the chances of the vast forest being declared a world heritage site. Their attacks failed to dent voter support for the NDP in last October's election.
Selinger said the government has spent money, "in the very low millions," to prepare the UNESCO bid.
There are more than 900 world heritage sites already designated by UNESCO, including Lunenburg, N.S., and Banff National Park.
The world heritage committee meets every spring to consider new sites, although it is not clear how soon the bid from Manitoba and Ontario will be considered.
This year the meeting is in St. Petersburg, Russia, but there is no guarantee the bid will be reviewed then.