Biographies in the Commons 1790-1820 volume
O’BRIEN, Sir Edward, 4th Bt. (1773-1837), of Dromoland, co. Clare.
O’BRIEN, Murrough, 5th Earl of Inchiquin [I] (1726-1808), of Taplow Court, Bucks.
O’CALLAGHAN, Cornelius, 1st Visct. Lismore [I] (1775-1857), of Shanbally Castle, co. Tipperary.
O’CALLAGHAN, James (1743-1836), of Heighington, co. Dur.
O’HARA, Charles (1746-1822), of Nymphsfield, co. Sligo.
O’NEILL, Hon. John Bruce Richard (1780-1855), of Tullymore Lodge, co. Antrim.
ODELL, William (1752-1831), of Fortwilliam and the Grove, Rathkeale, co. Limerick.
OGLANDER, Sir William, 6th Bt. (1769-1852), of Nunwell, I.o.W.
OGLE, George (1742-1814), of Belview, Enniscorthy, co. Wexford.
OGLE, Henry Meade (?1762-1823), of Drogheda, co. Louth.
OLIVER, Charles Silver (c.1763-1817), of Inchera, co. Limerick.
OMMANNEY, Francis Molyneux (?1774-1840), of 22 Norfolk Street, Strand, Westminster.
ONSLOW, Arthur (1759-1833), of Send Grove, nr. Guildford, Surr.
ONSLOW, Hon. Thomas (1754-1827), of Harley Street, Mdx. and West Clandon, Surr.
ONSLOW, Thomas Cranley (1778-1861), of Stoke Park, Surr.
ORCHARD, Paul (1739-1812), of Hartland Abbey, Devon.
ORD, William (1781-1855), of Whitfield Hall, Northumb.
ORDE, Sir John, 1st Bt. (1751-1824), of Burwash, Suss.
ORDE (afterwards ORDE POWLETT), Thomas (1746-1807), of Hackwood Park, nr. Basingstoke, Hants.
ORDE POWLETT, Hon. William Powlett (1782-1850), of Hackwood Park, Hants.
ORMSBY, Charles Montague (1767-1818), of Dublin.
OSBALDESTON, George (1786-1866), of Hutton Bushel and Ebberston Lodge, Yorks.
OSBORN, John (1772-1848), of Chicksands Priory, Beds.
OSBORNE, Lord Francis Godolphin (1777-1850), of Gogmagog Hills, Cambs.
OWEN, Sir Hugh, 6th Bt. (1782-1809), of Orielton, Pemb.
OWEN, John (1776-1861), of Orielton, Pemb.
OWEN, William (?1742-95), of Woodhouse, Salop and Bryngwyn, Llanfechain, Mont.