Sir Denis Stanislaus Henry, 1st Baronet, KBE,KC (7 March 1864 – 1 October 1925), was an Irish lawyer and politician who became the first Lord Chief Justice of Northern Ireland.
Henry's legal career flourished – he became Queen's Counsel in 1896 (which became King's Counsel on 21 January 1901 when Queen Victoria died), a Bencher of the King's Inns in 1898 and ultimately Father of the North-West Circuit – but his interest in politics did not diminish. In March 1905, he was a delegate at the inaugural meeting of the Ulster Unionist Council and in the North Tyrone by-election in 1907, he was the Unionist candidate, which he lost by a mere seven votes.
On 23 May 1916, he was elected as an MP in the South Londonderry by-election, the first by-election to be held in Ireland after the Easter Rising. The rebellion had had no discernible impact on the contest.
He married Violet Holmes, daughter of Hugh Holmes, a judge of the Court of Appeal in Ireland, and Olivia Moule of Elmley Lovett, Worcestershire. They had five children, including James Holmes Henry, who succeeded as second baronet. It was a mixed marriage as Violet was a staunch member of the Church of Ireland. Despite their religious difference, the marriage is said to have been happy.
He died in 1925, aged 61, and was buried near his native Draperstown.