Peerage of England
The ranks of the English peerage are, in descending order, Duke, Marquess, Earl, Viscount, and Baron. While most newer English peerages descend only in the male line, many of the older ones (particularly older baronies) can descend through females. Under English inheritance law all daughters are co-heirs, so many older English peerage titles have fallen into abeyance between various female co-heirs.
Peerage of Ireland
The last two grants of Irish peerages were: the promotion of the Marquess of Abercorn (a peerage of Great Britain) to be Duke of Abercorn in the Irish Peerage when he became Lord-Lieutenant of Ireland in 1868 and the granting of the Curzon of Kedleston barony to George Curzon when he became Viceroy of India in 1898. Peers of Ireland have precedence below peers of England, Scotland, and Great Britain of the same rank, and above peers of the United Kingdom of the same rank; but Irish peers created after 1801 yield to United Kingdom peers of earlier creation. Accordingly, the Duke of Abercorn (the junior Duke in the Peerage of Ireland) ranks between the Duke of Sutherland and the Duke of Westminster (both dukes in the Peerage of the United Kingdom).