Baron HolmPatrick, of HolmPatrick in the County of Dublin, is a title in the Peerage of the United Kingdom. It was created in 1897 for the Lord Lieutenant of County Dublin and former Member of Parliament for County Dublin, Ion Hamilton. Both his father, James Hans Hamilton, and grandfather, Hans Hamilton, had represented this constituency in the British Parliament. As of 2010[update] the title is held by the first Baron's great-grandson, the fourth Baron, who succeeded his father in 1991. He was active on the Labour benches in the House of Lords prior to the House of Lords Act 1999.
the heir presumptive to the barony is the current baron's brother, Hon. Ion Henry James Hamilton, b. 12 Jun 1956, as the baron's son is legitimized but not legitimate.