Question: What Canada US border town is located in the third-least populous Maine county and houses a population of 889 people?

Context paragraphs:
Washington County, Maine: Washington County is a county located in the U.S. state of Maine.  As of the 2010 census, its population was 32,856, making it the third-least populous county in Maine.  Its county seat is Machias.  The county was established on June 25, 1789.  It borders the Canadian province of New Brunswick.

Jefferson County, Mississippi: Jefferson County is a county located in the U.S. state of Mississippi; its western border is formed by the Mississippi River.  As of the 2010 census, the population was 7,726, making it the third-least populous county in Mississippi.  Its county seat is Fayette.  The county is named for U.S. President Thomas Jefferson.

Rich County, Utah: Rich County is a county located in the U.S. state of Utah.  As of the 2010 census, the population was 2,264, making it the third-least populous county in Utah.  Its county seat is Randolph, and the largest town is Garden City.  The county was created in 1864.  It was named for an early LDS apostle, Charles C. Rich.

McPherson County, Nebraska: McPherson County is a county located in the U.S. state of Nebraska.  As of the 2010 census, the population was 539, making it the third-least populous county in Nebraska and the eighth-least populous county in the United States.  Its county seat is Tryon.  The county was formed in 1890 from Logan County and named after Union General James B. McPherson.

Washington County, Vermont: Washington County is a county located in the U.S. state of Vermont.  Named after George Washington, its county seat is the municipality of Montpelier, the state capital.  As of the 2010 census, the population was 59,534, making it the third-most populous county in Vermont but the third-least populous capital county in the United States after Hughes County, South Dakota and Franklin County, Kentucky.  If Carson City, Nevada and Juneau Borough, Alaska are treated as counties, Washington County is the fifth-least populous capital county.

Pleasants County, West Virginia: Pleasants County is a county located in the U.S. state of West Virginia.  At the 2010 census, the population was 7,605, making it the third-least populous county in the state.  Its county seat is St. Marys.  The county was created by the Virginia General Assembly in 1851 and named for US Senator and Virginia Governor James Pleasants, Jr..

Perry, Maine: Perry is a town in Washington County, Maine, United States, on the Canada–United States border.  At the 2010 census, the town had a population of 889.

Ferry-Midway Border Crossing: The Ferry-Midway Border Crossing connects the town of Curlew, Washington with Midway, British Columbia on the Canada–US border.  Canada has had a customs office at this crossing since 1896, which coincided with the gold rush boom in the area.  As the mining boom subsided, the population of the town of Ferry, Washington waned, and has effectively disappeared.  The current US border station was built in 1936, and the Canada border station was built in 1951.  The US border station was listed on the US National Register of Historic Places 2014.

Kenedy County, Texas: Kenedy County is a county located in the U.S. state of Texas.  As of the 2010 census, its population was 416.  It is the third-least populous county in Texas and fourth-least populous in the United States.  Its county seat is Sarita.  The county was created in 1921 from parts of Hidalgo and Willacy counties and is named for Mifflin Kenedy, an early area rancher and steamboat operator.

King County, Texas: King County is a county located in the U.S. state of Texas.  As of the 2010 census, its population was 286, making it the second-least populous county in Texas and the third-least populous of any county in the United States.  King County has no incorporated communities.  Its county seat is the Census Designated Place of Guthrie.  The county was created in 1876 and organized in 1891.  It is named for William Philip King, who died at the Battle of the Alamo.

Supporting paragraphs: Perry, Maine Washington County, Maine
Answer: Perry