Per the Watertown Free Public Library, there is a memorial indicating Thomas Mayhew's home lot: "Stone on southwest side of Charles River Road: "Here by the ancient ford the landing and the weir was the homestall of Thomas Mayhew, a leader in Watertown affairs from 1635 to 1645. Afterwards with his son the Rev. Thomas Mayhew, he labored among the Indians at Martha's Vineyard." Thomas Mayhew, the father was the owner of the grist mill and a merchant. He owned 150 acres on the south side of the Charles River. Thomas Mayhew, the son, was a scholar and soon after moving to Martha's Vineyard, preached to the Indians. After his drowning, his father and sons took over the religious teachings. Thomas Mayhew, the father, built the first bridge over the Charles River - it was a foot bridge." Another site comments that this is about 200 yards east of Watertown Square along bankside Charles River Road.
There is a marker of Thomas Mayhew Jr. According to Insider's Guide to Martha's Vineyard by Polly Burroughs: "Begin at Memorial Park on Upper Main Street on the outskirts of Edgartown, where Edgartown-West Tisbury Road is clearly marked on the signs... Four and a half miles from Edgartown, on the left, is the Place on the Wayside, a stone marker in memory of Thomas Mayhew Jr., who often preached here to the Native Americans and was lost at sea at a young age."