Items in New York Heritage are organized into collections, which provide additional context for understanding their significance and meaning.

The Joseph H. Treyz Collection contains 149 patriotic envelopes printed during the Civil War.
The Lewis H. Brown Collection consists of sixty-four letters written by Lewis Henry Brown, Lewis’ brother Burritt Brown, and Albert Ransom, Burritt Brown’s friend and tent-mate.
Military Memories & Veterans' Voices was a program held at the Library on December 3rd, 2017. The collection consists of five oral histories and photographs.
Historic photographs of various military installations on Montauk.
The Patrick Casey Collection consists of an autobiographical narrative and two diaries.