| Billy Riley | |
| Position: | Outfielder |
| Birth Date: | 1855 |
| Birth Place: | Cincinnati, Ohio |
| Death Place: | Cincinnati, Ohio |
| Bats: | Right |
| Throws: | Right |
| Debutleague: | MLB |
| Debutdate: | May 4 |
| Debutyear: | 1875 |
| Debutteam: | Keokuk Westerns |
| Finalleague: | MLB |
| Finaldate: | September 30 |
| Finalyear: | 1879 |
| Finalteam: | Cleveland Blues |
| Statleague: | MLB |
| Stat1label: | Games played |
| Stat1value: | 51 |
| Stat2label: | Batting average |
| Stat2value: | .144 |
| Stat3label: | Runs batted in |
| Stat3value: | 10 |
| Teams: | |
William James Riley (1855–1887), nicknamed "Pigtail Billy", was an outfielder in Major League Baseball. He played for the 1875 Keokuk Westerns and the 1879 Cleveland Blues.[1]