The milestone two miles from the New Haven Green lies just over the city line in Hamden.
In 1906, industrialist Frederick Brewster bought 25 acres of land near the marker that had once belonged to Eli Whitney. He built a Tudor-style mansion, Edgerton, on the property.
The story is told that he wanted to buy his wife diamond jewelry, but she asked for a stone wall around the grounds instead. So the milestone was embedded into the wall.
Brewster's will specified that after his and his wife's death, the mansion be demolished and the grounds be donated to New Haven, becoming Edgerton Park.
It was a milestone for both the Hartford Turnpike and Cheshire Turnpike, which followed the same route from the Green to a point near the present Lake Whitney dam, where they separated.