V. Sir John Sinclair, fourth baronet of Stevenson, who married Martha, daughter and heiress of John Lockhart of Castlehill in the county of Lanark, one of the senators of the college of justice, and widow of Cromwell Lockhart of Lee, by whom he had eight sons and five daughters.
1. Sir Robert, his heir.
2. John, who, in virtue of a settlement of the estate of Castlehill made by his mother, assumed the name of Lockhart, succeeded to that estate, and married Charlotte, daughter of James Bogle, Esq; clerk to the signet, by whom he had three daughters.
3. George, who was bred to the law. In the year 1747 he was appointed sheriff of the county of Lanark, and in 1751 one of the senators of the college of justice, by the title of Lord Woodhall; and, upon the death of his brother John, without issue male, succeeded to the estate of Castlehill, but dying unmarried, that estate devolved upon his nephew James, as will be shown hereafter.
Sir John’s other sons, James, Charles, William, Thomas, and Patrick, all died unmarried
His other daughters, Katharine, Helen, Martha, and Margaret, all died unmarried.
Sir John died anno 1726, and was succeeded by his eldest son, Sir Robert Sinclair VI.
