 In 1858 J.B. Selkirk married Agnes Brown Bucham, a daughter of Mr and Mrs Robert Bucham of Hardacres, Kelso.They lived at 'Cascade', a house overlooking the Tweed midway between Selkirk and Galashiels before moving to Thornfield, Selkirk which was built by himself in 1870. he also built a villa in Cannes which he named Yarrow.Agnes to whom he was totally devoted was his incentive to write.