Sources: InFw2
- Samuel L. Clemens to Elisha Bliss, Jr., 9 March 1874 · Hartford, Conn · UCCL11969 InFw2
- Samuel L. Clemens to Olivia L. Clemens, 3 July 1874 · Hartford, Conn · UCCL01105 InFw2
- SLC to T. B. Pugh, 17 July 1874 · Elmira, N.Y · UCCL12672 InFw2
- Samuel L. Clemens to Jane T. Bigelow, 26 October 1875 · Hartford, Conn · UCCL11672 InFw2
- Bruce W. Munro to SLC, October 1881 · UCLC50361 InFw2
- SLC to Bruce W. Munro, 21 October 1881 · Hartford, Conn · UCCL11682 InFw2
- Bruce W. Munro to SLC, 15 June 1882 · Newcastle, Ont., Canada · UCLC50362 InFw2
- SLC to Karl Gerhardt, 21 September 1884 · Elmira, N.Y · UCCL00586 CU-MARK, InFw2
- SLC to Kingsland Smith, 23 January 1885 · St. Paul, Minn · UCCL09118 InFw2
- SLC to Clara L. Clemens, 25 December 1885 · Hartford, Conn · UCCL10670 InFw2
- SLC to Bruce W. Munro, 21 April 1886 · Hartford, Conn · UCCL11683 InFw2
- SLC to Joseph B. Gilder, 16 May 1886 · Hartford, Conn · UCCL11414 InFw2, TxAu3
- SLC to Bruce W. Munro, 2 February 1887 · Hartford, Conn · UCCL11684 InFw2
- SLC to Bruce W. Munro, 15 March 1887 · Hartford, Conn · UCCL11685 InFw2
- SLC to Bruce W. Munro, 22 March 1887, Hartford, Conn · UCCL10180 InFw2, CU-MARK
- SLC to Marcel Schwob, 4 November 1888 · Hartford, Conn · UCCL12680 InFw2, CBev6
- SLC to Thomas W. Knox, 24 February 1889 · Hartford, Conn · UCCL11670 InFw2
- SLC to Bruce W. Munro, 30 October 1889 · Hartford, Conn · UCCL12703 InFw2
- SLC per Franklin G. Whitmore to Bruce W. Munro, 12 February 1890 · Hartford, Conn · UCCL12679 InFw2
- SLC to Sherrard Clemens II, 1 September 1890 · Tannersville, N.Y · UCCL11676 InFw2
- SLC to Samuel S. McClure, 28 July 1891 · Aix-les-Bains, France · UCCL12675 InFw2
- SLC to William H. Rideing, 25 April 1894 · New York, N.Y · UCCL11674 InFw2
- SLC to Richard Edgcumbe, 4 May 1897 · London, England · UCCL12706 InFw2
- SLC to Chatto & Windus, June 1897 · London, England · UCCL12707 InFw2, CBev6
- SLC to Richard Edgcumbe, 23 July 1897 · Weggis, Switzerland · UCCL12708 InFw2
- SLC to Richard Edgcumbe, 29 July 1897 · Weggis, Switzerland · UCCL12709 InFw2
- SLC to Richard Edgcumbe, 22 August 1897 · Weggis, Switzerland · UCCL12687 InFw2
- SLC to Charles F. Mosher, 1 March 1898 · Vienna, Austria · UCCL12710 InFw2
- SLC to Chatto & Windus, 28 June 1898 · Kaltenleutgeben, Austria · UCCL10087 InFw2
- SLC to Bettina Wirth, 17 October 1898 · Vienna, Austria · UCCL12469 InFw2
- SLC to Wayne MacVeagh, 2 February 1899 · Vienna, Austria · UCCL12462 InFw2
- SLC to Mrs. William Manning, 4 July 1899 · London, England · UCCL11671 InFw2
- SLC to Richard Edgcumbe, 19 October 1899 · London, England · UCCL12711 InFw2
- SLC to William M. Clemens, 1 January 1900 · London, England · UCCL12034 InFw2
- SLC to Henry H. Rogers, 26 June 1902 · SS Kanawa · UCCL11971 InFw2
- SLC to Charles B. Dillingham, 13 July 1902 · York Harbor, Me · UCCL11344 InFw2
- SLC to Charles B. Dillingham, 22 August 1902 · York Harbor, Me · UCCL11677 InFw2
- SLC to Chauncey M. Depew, 23 October 1902 · Riverdale, N.Y · UCCL11724 InFw2
- SLC to Charles B. Dillingham, 27 October 1902 · Riverdale, N.Y · UCCL11678 InFw2
- SLC to Charles B. Dillingham, 9 November 1902 · Riverdale, N.Y · UCCL11679 InFw2
- SLC per Isabel V. Lyon to David A. Munro, 20 November 1902 · Riverdale, N.Y · UCCL06491 InFw2
- SLC to Virginia F. Boyle, 28 July 1904 · Tyringham, Mass · UCCL06844 InFw2
- SLC to Clara L. Clemens, 20 May 1905 · Dublin, N.H · UCCL07046 MoHM, InFw2
- SLC to Annie E. Trumbull, April 1906 · New York, N.Y · UCCL11354 InFw2
- SLC to Mary B. Rogers, August–October 1906 · Unknown place · UCCL13595 InFw2
- SLC to Clara L. Clemens, 5 March 1907 · New York, N.Y · UCCL07671 InFw2, NIC
- SLC to Unidentified, 20 September 1907 · Tuxedo Park, N.Y · UCCL12715 InFw2
- SLC to Isabel S. Wayland, 2 September 1908 · Redding, Conn · UCCL12712 InFw2
- SLC to John E. Wayland, 7 October 1908 · Redding, Conn · UCCL10517 InFw2
- SLC to Margery H. Clinton, 9 February 1909 · Redding, Conn · UCCL08343 InFw2
- SLC to To any friend or acquaintance of mine, 10 February 1909 · Redding, Conn · UCCL07666 InFw2
- SLC to Finley P. Dunne, 18 February 1909 · Redding, Conn · UCCL11681 InFw2
- SLC to Erna Heydweiller, 4 June 1909 · Redding, Conn · UCCL12676 InFw2
- SLC to Champ Clark, 16 September 1909 · Redding, Conn · UCCL11689 InFw2
- SLC to Francis E. Bliss, Unknown date · UCCL12714 InFw2
- SLC to ? Skinner, 23 May n.y. · New York, N.Y · UCCL09002 InFw2
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