21st Street was once Van Alst Avenue, named after a family of early settlers.
The station is still signed ‘21st Street–Van Alst’. The family’s patriarch, the Belgian Dutch sailor Joris Stevensen, settled in New Amsterdam in 1652 and bought land in Long Island City in 1670. Known as ‘de Caper van Alst’, the sailor from Aalst, he gave his descendants their surname. The street lost the name in the 1920s, when most named Queens streets were numbered.