According to many references on the internet, Matthew was born in Ireland, son of James, and immigrated around 1717, making it unlikely that he descended from these early RI Thorntons. Unless you can somehow connect his father James of Ireland as being related to the the RI Thorntons.
Easily searchable on the internet:
Try these websites :
" Matthew Thornton was born in Ireland in 1714. His parents emigrated to America when he was three. They first settled at Wiscasset, in Maine, but soon went to Worcester, Massachusetts, where Mathew received an academic education. He became a physician, and in 1745 was appointed surgeon to the New Hampshire troops in the expedition against Louisburg.
Thornton was then selected as the first President of the New Hampshire House of Representatives, and as a justice to the Superior Court, under the new constitution. He was also sent to the Continental Congress-too late to participate in the debates over Independence, but just in time to sign the Declaration on behalf of New Hampshire."
Died: June 24, 1803
Has additional generations after this:
"Children of Dr. Matthew & Hannah (Jack) THORNTON:
1. +James THORNTON, b 20 Dec 1763 Londonderry NH; d. 3 July 1817 in Merrimack NH, buried Thorton Cemetery, Merrimack NH; m. Mary Parker
2. Andrew THORNTON, b. abt 1766, died 22 Apr 1787, unmarried. Buried Thornton Cemetery, Merrimack NH
3. +Mary THORNTON, b. abt 1768 in Londonderry NH, d. 28 May 1845 Derry NH; m. 4 Sep 1791 to Hon Silas BETTON of Salem NH. He b. abt 1766 in Londonderry NH.
4. +Matthew THORNTON, b. abt 1770 in Londonderry NH married Fanny Curtis
5. +Hannah THORNTON, b 25 July 1774 in Merrimack NH, d. 18 May 1846 Cambridge MA married 13 Sep 1798 to John McGAW of Newburyport, Mass."
Reference: "The Family Of James Thornton, Father of the Honorable Matthew Thornton"; by Charles Thornton Adams; New York City, New York; 1905 (CS71. T49. 1905 LofC)·
ID: I08535 · Name:Matthew Thornton , MD · Sex: M · Birth: 1714 in Derry, Kilskerry Parish (Tyrone) Northern Ireland,The British Isles · Death: 24 JUN 1803 in Newburyport (Essex) Massachusetts · Burial: Thornton's Ferry Cemetery in Merrimack, New Hampshire ·