There are two different stories about this. One is that they came to Nantucket as ships’ ballast and were repurposed to pave Main Street and other streets. The other is that they were bought from Gloucester for the express purpose of paving Main Street.
Evidence for either story is circumstantial. There is no doubt that a large volume of cobblestones were used for paving Nantucket streets, and there was no source for them on-island. They must have come from somewhere else. It has been pointed out, however, that normally ships coming into Nantucket harbor were heavily laden with cargo and would not have been carrying ballast.
The paving of Main Street has been dated to 1837. This was when multiple large residences for wealthy owners were under construction from the intersection of Fair Street and Main up to the old town center at the intersection of Gardner, Milk, and Main Streets.
Town records indicate that concern was expressed in Town Meeting in 1836 about the potential widening of this stretch of Main Street and whether what was “going on” there should be approved. What was going on appears to have been paving at the expense of private owners. First it was voted to disapprove and then the vote was rescinded, indicating tacit approval.
A map created for the Nantucket Information Bureau in 1954 by R. Newton Mayall included the assertion that Main Street was “paved with cobblestones in 1837 brought from Gloucester.” When Mayall was asked about his source, he could not provide documentation.
Nantucket historian Dr. Will Gardner contacted a local historian in Gloucester who affirmed that there was a huge cache of cobblestones located on the waterfront of Gloucester and that cobbles from there had been shipped to Boston in times past, but he couldn’t say for sure that cobbles had also been shipped to Nantucket.