The White Plains Road Line is a rapid transit line of the A Division of the New York City Subway serving the central Bronx. It is mostly elevated and served both subway and elevated trains until 1952. The original part of the line, the part opened as part of the first subway was called the West Farms Division, and the extension north to 241st Street as part of the Dual Contracts was called the White Plains Road Line. Eventually, however, the two parts came to be known as the White Plains Road Line.

The Bronx is a borough of New York City, coextensive with Bronx County, in the U.S. state of New York. It is south of Westchester County; north and east of the New York City borough of Manhattan, across the Harlem River; and north of the New York City borough of Queens, across the East River. The Bronx is the only New York City borough not primarily located on an island. The Bronx has a land area of 42 square miles (109 km2) and a population of 1,472,654 in the 2020 census. If each borough were ranked as a city, the Bronx would rank as the ninth-most-populous in the U.S. Of the five boroughs, it has the fourth-largest area, fourth-highest population, and third-highest population density. The population density of the Bronx was 32,718.7 inhabitants per square mile (12,632.8/km2) in 2022, the third-highest population density of any county in the United States, behind Manhattan and Brooklyn. With a population that is 54.8% Hispanic as of 2020, it is the only majority-Hispanic county in the Northeastern United States and the fourth-most-populous nationwide.