Henry Warner Slocum, Jr. (May 28, 1862 – January 22, 1949) was an American male tennis player who was active in the late 19th century. Slocum won the 1888 Men's Singles title at the U.S. National Championships' in Newport against defending champion and compatriot Howard Taylor in straight sets. The next year he successfully defended his title in the Challenge Round with a victory over Quincy Shaw.

His other career highlights include winning the Rockaway Hunting Club Invitation three times (1886–1888), the Wentworth Open Tournament at Wentworth, New Hampshire (1887), the Staten Island Invitation (1887).

He was president of the United States National Lawn Tennis Association (USNLTA) in 1892 and 1893.

Legacy

Slocum was inducted into the International Tennis Hall of Fame in 1955. In 1890 he published a book titled Lawn Tennis in Our Own Country.

Grand Slam finals

Singles (2 titles, 2 runners-up)

{| class="sortable wikitable"

!style="width:40px"|Result

!style="width:50px"|Year

!style="width:170px"|Championship

!style="width:50px"|Surface

!style="width:160px"|Opponent

!style="width:170px" class="unsortable"|Score

|-style="background:#ccf;"

| style="background:#ffa07a;"|Loss ||1887 || U.S. Championships || Grass || Richard Sears|| 1–6, 3–6, 2–6

|-style="background:#ccf;"

| style="background:#98fb98;"|Win ||1888 || U.S. Championships || Grass || Howard Taylor|| 6–4, 6–1, 6–0

|-style="background:#ccf;"

| style="background:#98fb98;"|Win ||1889 || U.S. Championships || Grass || Quincy Shaw|| 6–3, 6–1, 4–6, 6–2

|-style="background:#ccf;"

| style="background:#ffa07a;"|Loss ||1890 || U.S. Championships || Grass || Oliver Campbell|| 2–6, 6–4, 3–6, 1–6

|}

Doubles (1 title, 2 runners-up)

{| class="sortable wikitable"

!style="width:40px"|Result

!style="width:50px"|Year

!style="width:170px"|Championship

!style="width:50px"|Surface

!style="width:160px"|Partner

!style="width:160px"|Opponents

!style="width:170px" class="unsortable"|Score

|-style="background:#ccf;"

| style="background:#ffa07a;"|Loss || 1885 || U.S. Championships || Grass || Percy Knapp || Joseph Clark <br /> Richard Sears || 3–6, 0–6, 2–6

|-style="background:#ccf;"

| style="background:#ffa07a;"|Loss || 1887 || U.S. Championships || Grass || Howard Taylor || James Dwight <br /> Richard Sears || 4–6, 6–3, 6–2, 3–6, 3–6

|-style="background:#ccf;"

| style="background:#98fb98;"|Win ||1889 || U.S. Championships || Grass || Howard Taylor || Valentine Hall<br> Oliver Campbell || 14–12, 10–8, 6–4

|}

<gallery caption="Allen & Genter Cigarettes" mode=packed heights=300>

File:H.W. Slocum, Jr., Lawn Tennis Champion of New England 1887-88, from World's Champions, Second Series (N43) for Allen & Ginter Cigarettes MET DP839302.jpg |From World's Champions, Second Series (N43) for Allen & Ginter Cigarettes, print. Litographer: Lindner, Eddy & Claus of New York

  • Slocum, Henry, Lawn Tennis in Our Own Country, 1890