Question: Estcourt Station - Pohénégamook Border Crossing connects the villages of Estcourt Station, a village in Big Twenty Township, Aroostook County, Maine, in which country?

Context paragraphs:
Frontier-Paterson Border Crossing: The Frontier-Paterson Border Crossing connects the town of Northport, Washington with Rossland, British Columbia on the Canada–US border.  It can be reached by Washington State Route 25 on the American side and British Columbia Highway 22 on the Canadian side.  Although Canada has had a customs office at or near the border since 1900, the US did not.  Until the mid-1960s, travelers entering from Canada at both this crossing and at the Boundary-Waneta border crossing were directed to proceed to the Customs office in Northport, Washington, several miles away.  The US built a border station at Frontier in 1965, and replaced it with a new station in 2011.  Canada continues to operate out of its 1950s-era border station.  This crossing is open 24 hours per day, 7 days per week.

Estcourt Station, Maine: Estcourt Station (elevation: 671 ft , pop.  4) is a village in Big Twenty Township, Aroostook County, Maine, United States.  It is the northernmost point in Maine and New England.

Hyder - Stewart Border Crossing: The Hyder - Stewart Border Crossing connects the communities of Hyder, Alaska and Stewart, British Columbia on the Canada–US border.  It can be reached by British Columbia Highway 37A from Stewart and International Street from Hyder.  There is no US border inspection station at this crossing, making it the only land border crossing where a person may legally enter the United States without reporting for inspection.  The US closed its border station, which was located in the same building as the Boundary Gift Shop, in the 1950s.  As a result, all flights leaving the Hyder Seaplane Base to other cities in Alaska are treated as international arrivals, and all passengers, including Hyder residents must be inspected by U.S. Customs and Border Protection officers.  Hyder is the easternmost community in Alaska.

Alburg Springs-Clarenceville Border Crossing: The Alburg Springs-Clarenceville Border Crossing connects the villages of Clarenceville, Quebec and Alburgh, Vermont on the Canada–United States border.  The border crossing is open daily between 8:00 AM and midnight.  Canada built a new border inspection station in 2005, while the US continues to use its Depression-era border station, listed on the National Register of Historic Places in 2014.

Estcourt Station - Pohénégamook Border Crossing: Estcourt Station - Pohénégamook Border Crossing connects the villages of Estcourt Station, Maine and Pohénégamook, Quebec on the Canada–US border.  The crossing is essentially a single small town divided by an international boundary.  Several of the buildings are bisected by the boundary line.  The US border station is located on the south end of town, where a road with access to other parts of Maine is located.  The Canada border station is in the center of town, where the railroad underpass provides access to other parts of Canada.  On the north end of Estcourt, there is an international pedestrian footbridge that crosses the St. Francis River.

Overton Corners–Lacolle 221 Border Crossing: The Overton Corners–Lacolle 221 Border Crossing connects the towns of Lacolle, Quebec to Champlain, New York on the Canada–United States border.  This crossing is open 24 hours per day, 365 days per year.  Because the village of Lacolle, Quebec has two border crossings, this one is called 221 to indicate it is the crossing on Quebec Route 221.  The other crossing is the Rouses Point - Lacolle 223 Border Crossing immediately to the east.  Conversely, the US Border station is sometimes called 276 because it is located on New York State Route 276.

Calais - Milltown Border Crossing: The Calais - Milltown Border Crossing connects the towns of Calais, Maine and St. Stephen, New Brunswick on the Canada–US border.  This crossing is located at the Milltown International Bridge.  Various bridges have existed at this location since 1825.  Canada built its border crossing station in 1967.  The US border station was built in 1938 and is planned to be replaced in 2014.

Big Twenty Township, Maine: The Big Twenty Township is an administrative division in Aroostook County in northern Maine.  It is one of the largest townships in Maine, and contains Estcourt Station, a village of four people that is the northernmost point in Maine.  The township also contains the northernmost point in New England and one of the northernmost points in the continental United States.

Pittsburg-Chartierville Border Crossing: The Pittsburg-Chartierville Border Crossing connects the towns of Chartierville, Quebec and Pittsburg, New Hampshire.  The crossing can be reached by U.S. Route 3 on the American side and by Quebec Route 257 on the Canadian side.  It is the only international land border crossing in the state of New Hampshire.  Pittsburg is notable for being the largest township (in terms of land area) in the continental United States.  Although the US operated a border station at Connecticut Lakes as far back as the 1930s, the facility consisted of a small one-room structure, and later a mobile home.  The US did not have a permanent inspection facility at the border until 1960, and the northernmost stretch of U.S. Route 3 remained unpaved until about 1970.  In 2012, the United States built a new border inspection facility.

Saint Francis River (Canada–United States): The St. Francis River (French: "Rivière Saint-François") is a river roughly 75 mi long, which forms part of the Canada–United States border.  The river rises ( ) in a lake of the same name located 12 mi east of the Rivière du Loup in Quebec.  The portion that forms the boundary starts at the bottom of Lake Pohenegamook at the very northernmost point of New England between Estcourt Station, Maine, and Estcourt, Quebec.  The river along the international boundary flows south and then south-east through two deep, narrow lakes to its mouth on the Saint John River at St. Francis, Maine/Saint-François-de-Madawaska, New Brunswick.

Supporting paragraphs: Estcourt Station - Pohénégamook Border Crossing Estcourt Station, Maine
Answer: United States