This old milestone, which stood on the Kingsbridge Road at least as far back as 1813, is now located on the grounds of the Morris-Jumel Mansion. Of the perhaps 40 or 50 milestones that once marked distances along various roadways in what is now NYC, this one is, to the best of my knowledge, one of only four originals that can still be found outdoors in the city.
You did lots of interesting homework for this one. Thanks!