Sources: ODa2
- Samuel L. Clemens to Henry M. Crane, 7 October 1868 · Hartford, Conn · UCCL02740
- Samuel L. Clemens to James Redpath per Telegraph Operator, 4 December 1869 · New York, N.Y · UCCL02445
- Samuel L. Clemens to Adolph H. Sutro, 11 June 1872 · Hartford, Conn · UCCL00755
- Samuel L. Clemens to Alfred Tennyson, 15 December 1873 · London, England · UCCL01006
- Samuel L. Clemens to Tom Taylor, per Charles Warren Stoddard, 29 December 1873 · London, England · UCCL01019
- Samuel L. Clemens to James Redpath, per Telegraph Operator, 3 March 1874 · Hartford, Conn · UCCL01060
- Samuel L. Clemens to James Redpath, per Telegraph Operator, 13 March 1874 · Hartford, Conn · UCCL08722
- Samuel L. Clemens to Herbert E. Hill, 3 November 1880 · Hartford, Conn · UCCL09943
- Samuel L. Clemens to James R. Osgood, 13 December 1880 · Hartford, Conn · UCCL01871
- SLC to Francis E. Bliss, 16 June 1881 · Branford, Conn · UCCL11208
- SLC to Elisabeth N. Fairchild, 6 October 1881 · Hartford, Conn · UCCL02045
- SLC to George William Curtis, 25 January 1882 · Hartford, Conn · UCCL09530
- SLC to Charles S. Fairchild, 20 June 1882 · Hartford, Conn · UCCL03243
- SLC to Edwin Pond Parker, 14 May–31 May 1883 · Hartford, Conn · UCCL11190
- SLC to OLC, Unknown date · Unknown place · UCCL11350
- SLC to A. R. Reasoner, 1 December 1885 · New York, N.Y · UCCL10348
- SLC to John R. Young, 7 December 1885 · Hartford, Conn · UCCL11207
- SLC to Unidentified, 16 September 1886 · Elmira, N.Y · UCCL10442
- SLC to William Smith, 3–4 February 1887 · Hartford, Conn · UCCL03522
- SLC to Lorettus S. Metcalf, 13 April 1888 · Hartford, Conn · UCCL03714
- SLC to O. E. Dunlap, 19 June 1888 · Hartford, Conn · UCCL11206
- SLC to Clarence C. Rice, 4 July 1888 · Elmira, N.Y · UCCL11191
- SLC to Frederick J. Hall, 28 December 1890 · Hartford, Conn · UCCL11205
- SLC to Edward W. Bok, 24 April 1891 · Hartford, Conn · UCCL04194
- SLC to Elisabeth N. Fairchild, 8 March 1892 · Menton, France · UCCL04273
- SLC to Henry M. Alden, 13 October 1892 · Florence, Italy · UCCL10567
- SLC to Susan L. Warner, 30 April 1893 · New York, N.Y · UCCL11654
- SLC to ? Parker, 31 December 1893 · New York, N.Y · UCCL09077
- SLC to Mary Mapes Dodge, 21 January 1894 · New York, N.Y · UCCL04676
- SLC to Henry H. Rogers, 22 August 1895 · Victoria, Canada · UCCL11201
- SLC to Henry H. Rogers, 30 August 1895 · RMS Warrimoo, en route from Vancouver, Canada, to Honolulu, Hawaii · UCCL11199
- SLC to Henry H. Rogers, 10 November 1895 · Timaru, New Zealand · UCCL11200
- SLC to Henry H. Rogers, 12 December 1895 · Wellington, New Zealand · UCCL11202
- SLC to J. Henry Harper, 5 December 1896 · London, England · UCCL09957
- SLC to Henry Preston Child, July 1897 · Unknown place · UCCL11198
- SLC to Ferdinand Gross, 10 October 1897 · Vienna, Austria · UCCL04708
- SLC to Unidentified, May 1898 · Vienna or Kaltenleutgeben, Austria · UCCL11221
- SLC to Edwin Pond Parker, 2 August 1898 · Kaltenleutgeben, Austria · UCCL05418
- SLC to Eva L. Farrell, 12 November 1899 · London, England · UCCL05706
- SLC to Alfred E. Ann, 20 February 1900 · London, England · UCCL08856
- SLC to Elizabeth MacAlister, 7 July 1900 · London, England · UCCL09364
- SLC to Chester S. Lord, 10 June 1902 · Riverdale, N.Y · UCCL06358
- SLC to Charles S. Fairchild, 13 August 1902 · York Harbor, Me · UCCL06404
- SLC to Henry L. Stoddard, 28 November 1902 · New York, N.Y · UCCL11218
- SLC to Louise M. Sill, 26 December 1902 · New York, N.Y · UCCL11175
- SLC to Charles S. Fairchild, 2 March 1903 · Riverdale, N.Y · UCCL06590
- SLC to Livingston Wright, 17 April 1903 · Riverdale, N.Y · UCCL06623
- SLC to Charles S. Fairchild, 14 May 1903 · Riverdale, N.Y · UCCL06659
- SLC to Mary Mapes Dodge, 18 December 1903 · Florence, Italy · UCCL06770
- SLC to Charles S. and Elisabeth N. Fairchild, 20 July 1904 · Lee, Mass · UCCL06891
- Jean Clemens to Isabel V. Lyon, 12 April 1905 · New York, N.Y · UCCL10754
- SLC per Isabel V. Lyon to Samuel J. Elder, 21 June 1905 · Dublin, N.H · UCCL07067
- SLC to Daisy Scott, 28 December 1905 · New York, N.Y · UCCL11222
- SLC to Charles D. Reid, January 1906 · New York, N.Y · UCCL11186
- SLC per Isabel V. Lyon to Alice M. Ditson, 5 March 1906 · New York, N.Y · UCCL11194
- SLC to Florence Watson Cadieu, 15 March 1906 · New York, N.Y · UCCL11188
- SLC to Unidentified, 12 April 1906 · New York, N.Y · UCCL11211
- SLC to Garth W. Cate, 25 November 1906 · New York, N.Y · UCCL11189
- SLC to Anita Moffett, December 1906 · Unknown place · UCCL11187
- SLC to George B. Harvey, 22 February 1907 · New York, N.Y · UCCL09982
- SLC to I. Benjamin Stone, July 1907 · London, England · UCCL11316
- SLC to Malcolm D. Graham, 25 May 1908 · New York, N.Y · UCCL10463
- SLC to Jeannette Cholmeley-Jones, August 1908 · Redding, Conn · UCCL11217
- SLC to Marguerite Schmitt, 24 September 1908 · Redding, Conn · UCCL09384
- SLC to Marion S. Allen, 31 January 1910 · Hamilton, Bermuda · UCCL10382
- SLC to Helen S. Allen, 31 January 1910 · Unknown place · UCCL10383
- SLC to Helen S. Allen, 6 March and April 8-11? 1910 · Hamilton, Bermuda · UCCL09914
- SLC to Julius G. Rathbun, 2 February n.y. · Hartford, Conn · UCCL11203
- SLC to W. S. Walton, Unknown date · Unknown place · UCCL11185
- SLC to Unidentified, Unknown date, Hartford, Conn · UCCL11184
- SLC to Unidentified, Unknown date · Unknown place · UCCL11178
- SLC to Unidentified, Unknown date · Unknown place · UCCL11177
- SLC to Lucy A. Perkins, Unknown date, Hartford, Conn · UCCL11180
- SLC to Isabel V. Lyon, Unknown date · Unknown place · UCCL11317
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