The first Baron Ashtown was succeeded according to the special remainder by his nephew, the second Baron (the son of Francis Trench). His grandson, the third Baron (son of Frederic Sydney Charles Trench, eldest son of the second Baron), sat in the House of Lords as an Irish Representative Peer from 1908 to 1915.
On the death of his younger son, the fifth Baron, this line of the family failed. The late Baron was succeeded by his first cousin once removed, the sixth Baron. He was the grandson of the Hon. William Cosby Trench, younger brother of the third Baron. However, he never married and on his death in 1990 this branch of the family also failed. The title was inherited by his second cousin once removed, the seventh holder of the title. He is the grandson of Hon. Cosby Godolphin Trench, second son of the third Baron.