List of closed New York City Subway stations
For reconstruction

Station
Division
Line
Borough
Closed
Reopened
Notes
Cortlandt Street
B (BMT)
Broadway Line
Manhattan
September 11, 2001
September 15, 2002
Closed when station sustained significant damage due to the September 11, 2001 attacks.
Cortlandt Street
B (BMT)
Broadway Line
Manhattan
August 20, 2005
November 25, 2009 (northbound) September 6, 2011 (southbound)
Closed a second time for the construction of the Dey Street Passageway and by request of the Port Authority of New York and New Jersey to facilitate the rebuilding of the World Trade Center site.
Cortlandt Street
A (IRT)
Broadway–Seventh Avenue Line
Manhattan
September 11, 2001
September 8, 2018
Closed when station sustained severe damage due to it being right underneath Ground Zero of the September 11, 2001 attacks. Station has since been rebuilt while reconstruction of the new World Trade Center site is being performed.
Intervale Avenue
A (IRT)
White Plains Road Line
Bronx
March 15, 1989
April 21, 1992
Closed due to station house arson in 1989, reopened after extensive reconstruction.
South Ferry (new)
A (IRT)
Broadway – Seventh Avenue Line
Manhattan
October 28, 2012
June 27, 2017
Flooded during Hurricane Sandy in October 2012. The outer South Ferry loop served as a temporary replacement while the new station was being rebuilt.

Question: What date did the Cortlandt Street station close in Manhattan, and what was the cause of the closure?
Answer: Cortlandt Street stations were closed in Manhattan in the aftermath of the September 11, 2001 attacks.