as there are no states that once bordered New York or Montana but no longer do so the answer could only be the states that once bordered Canada & no longer do so
& these are
in chronological order
Virginia Indiana Louisiana Missouri Nebraska & Oregon
tho the first of them only did so rather vaguely & only when it was still a colony
& all the others did so
even if more surely
only when they were still territories
Montana and North Dakota.
Montana,North Dakota,minnesota,Washington,and Alaska
Ten states share a land border with Canada: Alaska Idaho Maine Minnesota Montana New Hampshire New York North Dakota Vermont Washington The states above share a land border with Canada. Three additional states (Michigan, Ohio, and Pennsylvania) share a water border with Canada.
Washington, Idaho, Montana, North Dakota, Minnesota, New York, Vermont, New Hampshire, and Maine border Canada.
There are thirteen U.S. states that border Canada: Alaska, Washington, Idaho, Montana, North Dakota, Minnesota, Michigan, Ohio, Pennsylvania, New York, Vermont, New Hampshire, and Maine. All but Ohio and Pennsylvania form partial or complete land borders with Canada; Ohio and Pennsylvania share only water boundaries of Lake Erie with Canada.
Montana has the longer border of those 2 states with Canada.
Montana does, but many other states have longer borders with Canada
Montana is longer of those 2 states. But Alaska, Michigan, Maine and Minnesota are longer still.
canada
The state that borders Montana on the north is Alberta, Canada.
Washington and Montana.
The western states in the 48 contiguous states that have the longest border with Canada are Washington and Montana. Washington shares a border with British Columbia, while Montana shares a border with Alberta, Saskatchewan, and British Columbia.
Montana
Montana and North Dakota.
In the west, the state of Montana has the longest linear border with Canada. In the east, the state of Michigan has the longest border, including the Great Lakes.
Montana
Montana does.