Index: Papers of John Adams, Volume 21, O

• O’Bryen, Capt. Richard (of the Dauphin)
• Ochakiv, Ukraine
• Ogden, Rev. John Cosens (of Portsmouth, N.H.)
• Ogden Land Company
• Ohio
• Ohio Company (land firm)
• Ohio River
• Ojibwa Nation
• Old House (Peacefield, now Adams National Historical Park)
• Olive, Nicholas (French merchant)
• Oliver, Peter, Sr. (loyalist)
• Oneida County, N.Y.
• Oneida Lake, N.Y.
• Oneida Nation
• Onondaga Nation
• Orangists
• Øresund
• Orléans, Louis Philippe, Duc d’ (son of Philippe Égalité, later Louis Philippe I of France)
• Orléans, Louis Philippe Joseph, Duc d’ (Philippe Égalité)
• Osgood, Rev. David
• Ostend, Belgium
• Oswald, Richard (Brit. peace negotiator)
• Oswego, N.Y.
• Oswego County, N.Y.
• Otis, Harriet (daughter of Samuel, Sr.)
• Otis, Harrison Gray (Boston lawyer)
• Otis, James, Jr. (the Patriot)
• Otis, John (Senate clerk)
• Otis, Mary Smith Gray (wife of Samuel, Sr.)
• Otis, Samuel Allyne, Sr. (1740–1814, secy. of the Senate)
• Otis, Samuel Allyne, Jr. (1768–1814, son of Samuel, Sr.)
• Otsego County, N.Y.
• Ottawa Nation
• Ottoman Empire (Sublime Porte)
• Ouiatanon (Wea) Nation
• Overijssel (province of the Netherlands)
• Oxford University