[3] Current backers of the highway propose an east–west axis through northern and central Maine; these could cover up to three existing surface ports of entry on the U.S.-Canada border, two from Québec; and one from New Brunswick.

A potential obstacle to the eastern end of such an American highway could be the presence of the Moosehorn National Wildlife Refuge, as its Baring Division's easternmost extremities, on the American side, lie close to the International Avenue Bridge that crosses the St. Croix River, the international border in the area.

An additional crossing is anticipated further west between Vermont and Québec, with an expected linkup between Interstate 89, which already ends at the international border at the Highgate Springs–St.

[4] There are plans to complete the extension of Autoroute 35 from Saint-Sébastien to the border crossing at I-89's northern terminus by 2023, finally creating a freeway-to-freeway connection.

Continuous east–west freeway travel through (and within) northern New England is presently accomplished by three segments, only one of which is truly east–west: There are a handful of alternate east–west roadways, including US 2 between Montpelier, Vermont, and Bangor, Maine; US 302 between Montpelier and Portland, US 4 from the New York/Vermont border to Portsmouth, New Hampshire; and VT 9 /NH 9 between Bennington, Vermont, and the Concord, New Hampshire, area.