Question: In which American state in the New Engand region does Quebec Route 243 become Vermont Route 243?

Context paragraphs:
Ohio State Route 243: State Route 243 (SR 243) is an east–west state highway in the southern portion of the U.S. state of Ohio.  The western terminus of SR 243 is at a diamond interchange with the U.S. Route 52 (US 52) in Coal Grove.  The eastern terminus of the state highway is at its signalized junction with State Route 7 approximately 1.25 mi west of Proctorville near the northern banks of the Ohio River.

Vermont: Vermont ( ) is a state in the New England region of the northeastern United States.  It borders the other U.S. states of Massachusetts to the south, New Hampshire to the east, New York to the west, and the Canadian province of Quebec to the north.  Lake Champlain forms half of Vermont's western border with the state of New York and the Green Mountains run north-south the length of the state.

North Troy–Highwater Border Crossing: The North Troy–Highwater Border Crossing connects the town of Highwater, Quebec with North Troy, Vermont on the Canada–US border.  It is located at the meeting point of Vermont Route 243 and Quebec Route 243.  Both stations are open 24 hours per day for non-commercial traffic; the Canadian station is open to commercial traffic on weekdays during business hours.  The former US station facilities, dating to the 1930s, are listed on the National Register of Historic Places.

Virginia State Route 243: State Route 243 (SR 243) is a primary state highway in the U.S. state of Virginia.  Known as Nutley Street, the state highway runs 1.70 mi from U.S. Route 29 (US 29) and SR 237 near Merrifield north to SR 123 in Vienna.  SR 243 connects Vienna and Fairfax with Interstate 66 (I-66) and the Vienna station of the Washington Metro.

Vermont Route 235: Vermont Route 235 is a short state highway in Franklin County, Vermont, United States.  It runs from Vermont Route 120 in Franklin northwest to the Morses Line Border Crossing near the village of Morses Line, where it crosses into Quebec, Canada, and connects to Quebec Route 235, from which it derives its number.  The entire route is town-maintained and internally designated as major collector 299.

Washington State Route 243: State Route 243 (SR 243) is a 28.26 mi long state highway in the U.S. state of Washington, located entirely within Grant County and serving Desert Aire, Mattawa, Beverly and Vantage.  The roadway, which roughly parallels the Columbia River, begins at SR 24 southwest of Desert Aire and continues north past the Priest Rapids Dam and Wanapum Dam to SR 26 south of Vantage.  The road was established originally as a branch of Secondary State Highway 7C (SSH 7C) in 1957.  In 1964, the SSH 7C branch became SR 243 even though the road between SR 24 and Beverly was not complete until 1981.

Glen Cove Road: Glen Cove Road is a major north–south thoroughfare through north-central Nassau County on Long Island, New York, in the United States.  It is the main road leading to the communities on the east shore of Hempstead Harbor.  The portion south of the North Hempstead–Oyster Bay town line is the unsigned County Route 1 (CR 1), while the portion north of the town line until its intersection with NY 107 is designated as New York State Route 900B (NY 900B), an unsigned reference route, New York State Route 107 (NY 107), and County Route 243 (CR 243), an unsigned county route.

Quebec Route 243: Route 243 is a north/south highway on the south shore of the Saint Lawrence River.  Its northern terminus is in Saint-Félix-de-Kingsey at the junction of Route 255 and its southern terminus is in the township of Potton where it crosses the Canada–US border at the North Troy-Highwater Border Crossing into Vermont and becomes Vermont Route 243.  Route 243 is not a busy highway as it does not go through big towns.

Maryland Route 243: Maryland Route 243 (MD 243) is a state highway in the U.S. state of Maryland.  Known as Newtowne Neck Road, the state highway runs 4.66 mi from St. Francis Xavier Church near Compton north to MD 5 in Leonardtown.  MD 243 serves communities on the Newtowne Neck peninsula between St. Clements Bay to the west and Breton Bay to the east in central St. Mary's County.  The state highway was constructed between the early 1920s and early 1930s.  MD 243 was relocated at its northern terminus in the 1970s.

Vermont Route 243: Vermont Route 243 is a 1.181 mi state highway located within the village of North Troy in Orleans County, Vermont, United States.  The route runs from the Canada–United States border at Potton, where the road continues into Quebec past the North Troy–Highwater Border Crossing as Route 243, to VT 105 in the village center.

Supporting paragraphs: Quebec Route 243 Vermont
Answer: Vermont