The person he was based on, William Poole, was buried in Greenwood Cemetery in Brooklyn, I don’t exactly know why, but they did have boats, so maybe it wasn’t that inconvenient, but I would like to know too.

Edit: from an article I found

“Bill The Butcher Poole had one of the largest funerals ever seen in the city of New York City, with thousands of mourners following the casket from Christopher Street to the Battery where a ferry took the remains to Green-Wood Cemetery. It was reported that so many people stood on the roofs of buildings to watch the procession that one house collapsed under the weight killing four people. John Morrissey organized an array of Five Points thugs including the “Original Hounds” Engine Number 36 and a gang called the Short Boys to throw rocks and bricks at the mourners.”