On 15 Mar 1753 when Josiah was 32, he first married Mary Dorr (35394) , daughter of Capt. Ebenezer Dorr (16922) (25 Jan 1687/8-25 Feb 1760) & Mary Boardman (6 May 1689-12 Jun 1728), in Roxbury, MA. Born on 25 Jan 1718 in Roxbury, MA.78 Mary died in Woburn, MA, on 11 Nov 1753; she was 35. Buried in First Burial Ground of Woburn.144 Marriage intention published on 15 Aug 1752.

Headstone:144
“Here lyes ye body of Mrs. Mary Peirce, Wife to Mr. Josiah Peirce, Jun'r., who died November ye 11th, 1753, in ye 36th year of her age. Also Mary, their daughter, died December 28th, 1753, aged 2 months and 2 days”

On 15 Jan 1756 when Josiah was 35, he second married Ruth Simonds (22555) , daughter of Lieut. James Simonds (8448) (1 Nov 1686-29 Jul 1775) & Mary Fowle (19976) (18 Jun 1689-9 Mar 1762).256 Born on 10 Oct 1730 in Woburn, MA.124 Ruth died in Baldwin, Hancock County, Maine, on 18 Jun 1811; she was 80.256