The collection is composed of correspondence to Richard Oswald (1705-1784) and the correspondence of Richard Alexander Oswald, M.P. (1771-1841), his cousin James Oswald, M.P., and the latter's nephew Alexander Oswald, M.P., all of whom had succeeded in turn to the Auchincruive estates. More specifically there is: a batch of letters to Richard Oswald of Auchincruive from various correspondents in Scotland relating to the management of his Scottish estates and to business transactions, 1764-1884; letters of Richard Oswald Alexander to D. Campbell, 1836-1837, and letters to Oswald from various correspondents including J. Kermack, W.S. 1804-1826. And also: a letter from A. Oswald to R. A. Oswald in Italy, 1817; letters of Alexander Oswald to R. Oswald, 1774-1778; letter from Alexander Oswald to his aunt Miss E. Oswald, describing the coronation of Queen Victoria, 1838; letter of Alexander Oswald to his sisters at Ardrossan, 1839; letters to Alexander Oswald from brother, sister, aunts, Uncle James Oswald M.P., and grandmother, and also from the 10th Duke of Hamilton and from Messrs. Dundas and Wilson, 1829-1845; letters of George Oswald to R. Oswald, 1769-1772; letter of George Oswald to his brother Alexander, 1841; letter to George Oswald from A. Hain, 1793; letter of J, Oswald to R. A. Oswald in Paris, 1817; letters of James Oswald M.P. to his nephew Alexander Oswald, 1829-1843; letter of James Oswald M.P. to his sister Miss Oswald, 1838; letters to James Oswald M.P. from various correspondents, 1838-1846; letters of Mrs. Margaret Oswald to her grandson Alexander Oswald in Madeira and Pau, 1829; and, letters of Mrs. Margaret Oswald to her nephew Alexander Oswald, 1829 and 1831.