Shortly after his marriage in 1775, his career was interrupted by the beginning of the AmericanRevolutionary War. Barclay served with distinction, as a major, in the "Loyal American Regiment", in the British Loyalist forces, throughout the war and, with the confiscation of his New York property and having been named specifically in a Bill of Attainder in that state, he chose to join the loyalists heading to Canada.
Resettlement in British Canada
After considering New Brunswick, Thomas Henry Barclay opted for Nova Scotia where the forces were given land grants. At one point, he had moved to Annapolis Royal and began a law practice. In 1785, he was elected to the 6th General Assembly of Nova Scotia representing Annapolis County while Edmund Fanning was governor. The next year, John Parr became governor. In 1793, Barclay was elected for Annapolis Township and served as speaker for the assembly. He also served as lieutenant-colonel in the colony's militia and was boundary commissioner for the British when the border between the United States and New Brunswick was settled in Jay's Treaty. Although he was appointed to the Council for Nova Scotia in 1799, he was given the post of British consul general in New York City later that year. Following the War of 1812, he became a member of another boundary commission dealing with another section of the border with the United States. In 1822, he settled at a country home on Manhattan.
Personal life
In 1775, Thomas Henry Barclay married Susan DeLancey, a granddaughter of Stephen Delancey. Together, they were the parents of 12 children, including:
Henry Barclay, who married Catherine Watts, daughter of Robert Watts, in 1817.
DeLancey Barclay, who married Mary Fairfield, widow of Gurney Barclay, in 1825.
Maria Barclay, who married Simon Fraser in 1806.
Thomas Edmund Barclay, who married Catherine Smith Channing, daughter of Walter Channing, in 1821.
Susannah Barclay, who married Peter Gerard Stuyvesant, in 1803. After her death, he married Helena Rutherfurd.
Anne Barclay, who married William Burrington Parsons in 1815. They were the grandparents of William Barclay Parsons.
George Barclay, who married Louise Matilda Aufrere, in 1818.
Anthony Barclay, who married Anna Matilda Waldburg, daughter of J. Bartholomew Waldburg, in 1816, who took over as British Commissioner under the 6th and 7th articles of the Treaty of Ghent.
Henry Barclay, who married Sarah Ann Moore, daughter of Daniel Sackett Moore, in 1842. They were the parents of James Lent Barclay.
Thomas Henry Barclay died there in 1830 and was buried in the Bowery.
