Sources: DLC
- SLC to Anson Burlingame or Edward L. Burlingame, 7 July 1866 · Honolulu, Hawaii · UCCL10786
- Samuel L. Clemens to John Russell Young, 22 November 1867 · Washington, D.C · UCCL00157
- Samuel L. Clemens to John Russell Young, 24 November 1867 · Washington, D.C · UCCL00159
- Samuel L. Clemens to John Russell Young, 25 November 1867 · Washington, D.C · UCCL00161
- Samuel L. Clemens to John Russell Young, 1 December 1867 · Washington, D.C · UCCL00164
- Samuel L. Clemens to John Russell Young, 4 December 1867 · Washington, D.C · UCCL00168
- Samuel L. Clemens to Charles John Russell Young, 1 February 1868 · Washington, D.C · UCCL00188
- Samuel L. Clemens to Anson Burlingame, 19 February 1868 · Washington, D.C · UCCL00195
- Samuel L. Clemens to John Russell Young, 8–10 March 1869 · Hartford, Conn · UCCL00270
- Samuel L. Clemens to Whitelaw Reid, 15 June 1869 · New York, N.Y · UCCL00317
- Samuel L. Clemens to Whitelaw Reid, 26 June 1869 · Elmira, N. Y · UCCL00323
- Samuel L. Clemens to Whitelaw Reid, 15 August 1869 · Buffalo, N. Y · UCCL00334
- Samuel L. Clemens to Whitelaw Reid, 7 September 1869 · Buffalo, N.Y · UCCL00350
- Samuel L. Clemens to Oliver Wendell Holmes, 30 September 1869 · Buffalo, N.Y · UCCL00360
- Samuel L. Clemens to Ainsworth R. Spofford, 10? October 1870 · Buffalo, N.Y · UCCL00507
- Samuel L. Clemens to Whitelaw Reid, 8 November 1870 · Buffalo, N.Y · UCCL00529
- Samuel L. Clemens to Whitelaw Reid, 26 December 1870 · Buffalo, N.Y · UCCL02791
- Samuel L. Clemens to Whitelaw Reid, 31 December 1870 · Buffalo, N.Y · UCCL02793
- Samuel L. Clemens to Whitelaw Reid, 22 February 1871 · Buffalo, N.Y · UCCL00581
- Samuel L. Clemens to Whitelaw Reid, 29 April 1871 · Elmira, N.Y · UCCL00607
- Samuel L. Clemens to Whitelaw Reid, 27 June 1871 · Elmira, N.Y · UCCL00624
- Samuel L. Clemens to James Redpath, 10 July 1871 (2nd of 3) · Elmira, N.Y · UCCL00635
- Samuel L. Clemens to Louise Chandler Moulton, 18 June 1872 · Hartford, Conn · UCCL00757
- Samuel L. Clemens to Whitelaw Reid, 3 January 1873 · 2nd of 2 · Hartford, Conn · UCCL00852
- Samuel L. Clemens to Whitelaw Reid per Telegraph Operator, 3 January 1873 · 1st of 2 · Hartford, Conn · UCCL00851
- Samuel L. Clemens to Whitelaw Reid per Telegraph Operator, 6 January 1873 · Hartford, Conn · UCCL00853
- Samuel L. Clemens to Whitelaw Reid, 13 and 17 January 1873 · Hartford, Conn · UCCL00857
- Samuel L. Clemens to Whitelaw Reid, 25 January 1873 · Hartford, Conn · UCCL00865
- Samuel L. Clemens to Whitelaw Reid, per Telegraph Operator, 1 February 1873 · Hartford, Conn · UCCL00871
- Samuel L. Clemens to Whitelaw Reid, 18 February 1873 · Hartford, Conn · UCCL00874
- Samuel L. Clemens to Whitelaw Reid, per Telegraph Operator, 7 March 1873 · 1st of 2 · Hartford, Conn · UCCL00882
- Samuel L. Clemens to Whitelaw Reid, 7 March 1873 · 2nd of 2 · Hartford, Conn · UCCL00883
- Samuel L. Clemens to Whitelaw Reid, 28 March 1873 · Hartford, Conn · UCCL00892
- Samuel L. Clemens to Whitelaw Reid, 9 April 1873 · Hartford, Conn · UCCL00899
- Samuel L. Clemens to Whitelaw Reid, 17? April 1873 · Hartford, Conn · UCCL00902
- Samuel L. Clemens to Whitelaw Reid, 20 April 1873 · Hartford, Conn · UCCL00903
- Samuel L. Clemens and Charles Dudley Warner to Ainsworth R. Spofford, 21 April 1873 · Hartford, Conn · UCCL00904
- Samuel L. Clemens to Whitelaw Reid, 22 April 1873 · Hartford, Conn · UCCL00907
- Samuel L. Clemens to Whitelaw Reid, 22 April 1873 · Hartford, Conn · UCCL00906
- Samuel L. Clemens to Whitelaw Reid, 22 April 1873 · Hartford, Conn · UCCL00905
- Samuel L. Clemens to John Russell Young, 6 or 7 January 1874 · London, England · UCCL01016
- Samuel L. Clemens to Louise Chandler Moulton, 13 February 1874 · Hartford, Conn · UCCL01049
- Samuel L. Clemens to Thomas Bailey Aldrich, 24 March 1874 · Hartford, Conn · UCCL01068
- Samuel L. Clemens to Ainsworth R. Spofford, 7 May 1874 · Elmira, N.Y · UCCL01084
- Samuel L. Clemens to Ainsworth R. Spofford, 21 May 1874 · Elmira, N.Y · UCCL01092
- Samuel L. Clemens to Anna E. Dickinson, 28 June 1874 · Elmira, N.Y · UCCL01104
- Samuel L. Clemens to Thomas Bailey Aldrich, 8 July 1874 · Elmira, N. Y · UCCL01108
- Samuel L. Clemens to Anna E. Dickinson, 8–10 July 1874 · Elmira, N. Y · UCCL01106
- Samuel L. Clemens to Henry Watterson, 9 October 1874 · Hartford, Conn · UCCL01136
- Samuel L. Clemens to Louise Chandler Moulton, 14 October 1874 · Hartford, Conn · UCCL01139
- Samuel L. Clemens to Louise Chandler Moulton, 8 January 1875 · Hartford, Conn · UCCL01176
- Samuel L. Clemens to Ainsworth R. Spofford, 16 February 1875 · Hartford, Conn · UCCL01194
- Samuel L. Clemens to James G. Blaine, 11 October 1875 · Hartford, Conn · UCCL00552
- Samuel L. Clemens to Ainsworth R. Spofford, 23 October 1876 · Hartford, Conn · UCCL02467
- Samuel L. Clemens to Ainsworth R. Spofford, 18 July 1877 · Hartford, Conn · UCCL12308
- Samuel L. Clemens to Richard Whiteing, 17 May 1879 · Paris, France · UCCL01656
- Samuel L. Clemens to Thomas Bailey Aldrich, 25 May 1879 · Paris, France · UCCL01658
- Samuel L. Clemens to Elizabeth S. Stevens, 12 June 1879 · Paris, France · UCCL01667
- Samuel L. Clemens to Ainsworth R. Spofford, 26 September 1879 · Elmira, N.Y · UCCL01693
- Samuel L. Clemens to Ainsworth R. Spofford, 11 March 1880 · Hartford, Conn · UCCL01770
- SLC to Chester A. Arthur, 15 September, 1880 · Elmira, N.Y · UCCL13240
- SLC to John R. Young, 21 February 1881 · Hartford, Conn · UCCL01913
- SLC to John R. Young, 8 April 1881 · Hartford, Conn · UCCL02412
- SLC to John R. Young, 29 April 1881 · Hartford, Conn · UCCL01941
- SLC to John Esten Cooke, 17 August 1881 · Elmira, N.Y · UCCL02010
- SLC to John R. Young, 9 January 1882 · Hartford, Conn · UCCL02146
- SLC to John R. Young, 3 February 1882 · Hartford, Conn · UCCL02156
- SLC to John R. Young, 6 March 1882 · Hartford, Conn · UCCL02170
- SLC to John R. Young, 13 March 1882 · Hartford, Conn · UCCL02171
- SLC to John R. Young, 20 March 1882 · Hartford, Conn · UCCL02175
- SLC to John R. Young, 25 April 1882 · Arkansas City, Ark · UCCL02207
- Samuel L. Clemens to Ainsworth R. Spofford, 3 June 1882 · Hartford, Conn · UCCL13099
- SLC to Benjamin H. Ticknor, 14 March 1883 · Hartford, Conn · UCCL11153
- SLC to Ainsworth R. Spofford, 28 February 1884 · Hartford, Conn · UCCL02924
- SLC to Unidentified, 1 March 1885 · Hartford, Conn · UCCL10787
- SLC to Richard R. Bowker, 23 July 1885 · Unknown place · UCCL11152
- SLC to Richard R. Bowker, 23 July 1885 · Elmira, N.Y · UCCL11151
- SLC to William T. Sherman, 19 September 1885 · Hartford, Conn · UCCL01606
- SLC to Grover Cleveland, 23 September 1885 · Hartford, Conn · UCCL03290
- SLC to William T. Sherman, 5–6 October 1885 · Hartford, Conn · UCCL04126
- SLC to William T. Sherman, 12 October 1885 · Hartford, Conn · UCCL03859
- SLC to William T. Sherman, 15 December 1885 · Hartford, Conn · UCCL03977
- SLC to William C. Prime, 31 January 1886 · New York, N.Y · UCCL03985
- SLC to Grover Cleveland, 23 February 1886 · Hartford, Conn · UCCL03371
- SLC to John R. Young, 20 January 1887 · Hartford, Conn · UCCL03514
- SLC to George Iles, 24 January 1887 · Hartford, Conn · UCCL03517
- SLC to Grover Cleveland, 10 September 1887 · Elmira, N.Y · UCCL03648
- SLC to Richard Watson Gilder, 4 March 1888 · Hartford, Conn · UCCL11150
- SLC to Frances F. Cleveland, 22 March 1888 · Washington, D.C · UCCL03710
- SLC to Grover Cleveland, 20 February 1889 · Hartford, Conn · UCCL03865
- SLC to Frederick J. Hall and Daniel Carter Beard, 24 July 1889 · Elmira, N.Y · UCCL03916
- SLC to Daniel Carter Beard, 28 August 1889 · Elmira, N.Y · UCCL03933
- SLC to John R. Young, 13 July 1890 · New York, N.Y · UCCL04063
- SLC to John R. Young, 14 July 1890 · New York, N.Y · UCCL09116
- SLC to John R. Young, 6 August 1890 · Tannersville, N.Y · UCCL04073
- SLC to John R. Young, 8 October 1890 · New York, N.Y · UCCL04099
- SLC to Gardiner Greene Hubbard, 27 December 1890 · Hartford, Conn · UCCL12069
- SLC to John R. Young, 7 February 1891 · Hartford, Conn · UCCL11160
- SLC to William Tecumseh Sherman, 13 February 1891 · Hartford, Conn · UCCL13117
- SLC to William F. Whitmore, May 1891 · Hartford, Conn · UCCL09709
- OLC to Frederick J. Hall, 21 January 1892 · Berlin, Germany · UCCL04266
- SLC to Frederick J. Hall, 4–5 September 1892 · Bad Nauheim, Germany · UCCL04653
- SLC to Webster (C. L.) & Co., 11 October 1892 · Florence, Italy · UCCL10091
- SLC to Ruth Cleveland, 3 November 1892 · Florence, Italy · UCCL02398
- SLC to Owen Wister, 4 August 1895 · Helena, Mont · UCCL12514
- SLC to Andrew S. Burt, 12 December 1896 · London, England · UCCL13257
- SLC to Ainsworth R. Spofford, 19 May–12 July 1897 · London, England · UCCL05218
- SLC to Francis E. Bliss, 31 May 1897 · London, England · UCCL04430
- SLC to John M. Hay, 2 February 1899 · Vienna, Austria · UCCL05540
- SLC to John M. Hay, 11 March 1899 · Vienna, Austria · UCCL05560
- SLC to John M. Hay, 4 May 1899 · Vienna, Austria · UCCL05586
- SLC to John M. Hay, 27 February 1900 · London, England · UCCL05764
- SLC to Andrew Carnegie, 17 May 1900 · London, England · UCCL05806
- SLC to Andrew Carnegie, 8 July 1900 · London, England · UCCL05832
- SLC to Burton Harrison, 15 December 1900 · New York, N.Y · UCCL05933
- SLC to N. F. Griswold, 20 December 1900 · New York, N.Y · UCCL05937
- SLC to Andrew Carnegie, 6 February 1901 · New York, N.Y · UCCL05990
- SLC to William Augustus Croffut, 8 February 1901 · New York, N.Y · UCCL12550
- SLC to Albert Sonnichsen, 18 March 1901 · New York, N.Y · UCCL06021
- SLC to Elizabeth W. Gilbert, 19 June 1901 · New York, N.Y · UCCL06075
- SLC to American people, 4 July 1901 · New York, N.Y · UCCL11648
- SLC to Mary D. Young, 29 September 1901 · New York, N.Y · UCCL06148
- SLC to Andrew Carnegie, 21 November 1901 · Riverdale, N.Y · UCCL06173
- SLC to Daniel Carter Beard, 11 December 1901 · Riverdale, N.Y · UCCL12540
- SLC to Frederick A. Duneka, 21 December 1901 · Riverdale, N.Y · UCCL12506
- SLC to Theodore Roosevelt, 24 December 1901 · Riverdale, N.Y · UCCL06196
- SLC to Frederick A. Duneka, 18 January 1902 · Riverdale, N.Y · UCCL06248
- SLC to Daniel Carter Beard, 18 January 1902 · Riverdale, N.Y · UCCL06247
- SLC to Frederick A. Duneka, 16 February 1902 · Riverdale, N.Y · UCCL06279
- SLC to Ernest H. Crosby, 13 April 1902 · Riverdale, N.Y · UCCL09037
- SLC to Everett Gill, 1 June 1902 · Hannibal, Mo · UCCL06349
- SLC to Isaac K. Funk, 16 July 1902 · York Harbor, Me · UCCL11159
- SLC to Frederick A. Duneka, 19 September 1902 · York Harbor, Me · UCCL06435
- SLC to Frederick A. Duneka, 6 October 1902 · York Harbor, Me · UCCL06454
- SLC to Daniel Carter Beard, 12 December 1902 · Riverdale, N.Y · UCCL06513
- SLC to Alexander McDowell McCook, 20 January 1903 · Riverdale, N.Y · UCCL06569
- SLC to Annie Colt McCook, 18 February 1903 · Riverdale, N.Y · UCCL06583
- SLC to John M. Hay, 11 March 1903 · Riverdale, N.Y · UCCL06596
- SLC to Frederick A. Duneka, 27 April 1903 · Riverdale, N.Y · UCCL06634
- SLC to Henry H. Rogers, 10 September 1903 · New York, N.Y · UCCL09708
- SLC to Frederick A. Duneka, 21 October 1903 · New York, N.Y · UCCL06748
- SLC to Frederick A. Duneka, 5 January 1904 · Florence, Italy · UCCL06782
- SLC to John M. Hay, 21 June 1904 · Florence, Italy · UCCL06850
- SLC to Daniel Carter Beard, 30 March 1905 · New York, N.Y · UCCL12539
- SLC to Frederick A. Duneka, 16 September 1905 · Dublin, N.H · UCCL07137
- SLC to Louise C. Moulton, November 1905 · Unknown place · UCCL07189
- SLC to Herbert Putnam, 21 November 1905 · New York, N.Y · UCCL07216
- SLC to Andrew Carnegie, 2 December 1905 · New York, N.Y · UCCL11154
- SLC to Booker T. Washington, 6 January 1906 · New York, N.Y · UCCL12544
- SLC to Andrew Carnegie, 1 February 1906 · New York, N.Y · UCCL11155
- SLC to Andrew Carnegie, 10 February 1906 · New York, N.Y · UCCL07337
- SLC to Grover Cleveland, 6 March 1906 · New York, N.Y · UCCL07365
- SLC to Andrew Carnegie, 26 November 1906 · New York, N.Y · UCCL11156
- SLC per Isabel V. Lyon to Finley P. Dunne, 14 January 1907 · New York, N.Y · UCCL07627
- SLC to Frederick A. Duneka, 30 April 1907 · SS Kanawha · UCCL07699
- SLC to Whitelaw Reid, 3 May 1907 · New York, N.Y · UCCL07710
- SLC to Andrew Carnegie, 4 July 1907 · London, England · UCCL07776
- SLC to Annie Colt McCook, 19 September–20 September 1907 · Tuxedo Park, N.Y · UCCL10788
- SLC to Andrew Carnegie, 22 January 1908 · New York, N.Y · UCCL08897
- SLC, Isabel V. Lyon to William Augustus Croffut, 16 February 1908 · New York, N.Y · UCCL07939
- SLC to Andrew Carnegie, 28 April 1908 · New York, N.Y · UCCL11157
- SLC to Augusta M. D. Ogden, 27 June 1908 · Redding, Conn · UCCL08304
- SLC to John M. Howells, 3 July 1908 · Redding, Conn · UCCL08899
- SLC to Andrew Carnegie, 26 March 1909 · Redding, Conn · UCCL11158
- SLC to Frederick A. Duneka, 12 April 1909 · Redding, Conn · UCCL08382
- SLC to Augusta M. D. Ogden, 22 September 1909 · Redding, Conn · UCCL08458
- SLC to Augusta M. D. Ogden, 13 October 1909 · Redding, Conn · UCCL08467
- SLC to Augusta M. D. Ogden, 19 October 1909 · Redding, Conn · UCCL08472
- SLC to Augusta M. D. Ogden, 30 October 1909 · Redding, Conn · UCCL08480
- SLC to Andrew Carnegie, 4 February 1910 · Hamilton, Bermuda · UCCL08554
- SLC to Frederick A. Duneka, 17 April n.y. · Unknown place · UCCL01823
- SLC to George B. McClellan, Unknown date · Unknown place · UCCL05526
- SLC to Daniel Carter Beard, Unknown date · Unknown place · UCCL08739
- SLC to Andrew Carnegie, Unknown date, New York, N.Y · UCCL08594
- SLC to Andrew Carnegie, Unknown date, New York, N.Y · UCCL08592
- SLC to Andrew Carnegie, Unknown date, New York, N.Y · UCCL08591
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