@MxxCon: My sources for the data are the art galleries' websites. I have visited the art galleries in this area for 15+ years so I am familiar with the art gallery locations. I am then using their websites the populate the remaining data. All of the data in the edits are available directly on their websites.

@hrhino @MxxCon: Marianne Boesky has two locations (507 and 509 West 24th Street). Their website (https://marianneboeskygallery.com/about/) has pictures of their locations. As one of the pictures shows, one of the locations is indeed directly under the High Line.