Did you see George Blecher’s article, “Murder, Politics and Architecture: The Making of Madison Square Park” in the recent New York Times? https://nyti.ms/2OEDbk1
It’s a fascinating article about the area, with historical photos and background. Readers of mysteries and other books will find all kinds of connections if you look carefully. There’s a beautiful photo of the Flatiron Building, the current home of Macmillan publishers. There’s a story about Senator Roscoe Conkling and his death during the Great Blizzard of 1888. That story is part of Rosemary Simpson’s historical mystery set during the Gilded Age, What the Dead Leave Behind.
You can find Simpson’s books about New York in the Web Store. http://bit.ly/2OJxMYM
And, I’m sure you’ll find other historical mysteries about New York City, including Rhys Bowen’s Molly Murphy books, Caleb Carr’s books, such as The Alienist, Lyndsay Faye’s The Gods of Gotham. Don’t hesitate to ask the Poisoned Pen staff for help.