| 100% | RANGER | 6 | __ 4; first US spacecraft to reach the Moon |
| 47% | LUNA | 4 | ___ 9, first spacecraft to land softly on the moon |
| 47% | LUNA | 4 | ___ II, first man-made object to reach the moon |
| 46% | STLOUIS | 7 | First US city to host the Olympic Games |
| 46% | BALBOA | 6 | First European explorer to reach the Pacific, 1513 |
| 46% | RAN | 3 | Tried to reach the finishing ribbon first, perhaps |
| 46% | HARRIS | 6 | Stayce, first African American to reach three star general rank in the US Air Force (2016) |
| 45% | BOBBEAMON | 9 | US long-jumper, the first to reach 29ft |
| 45% | RITA | 4 | First Nobel laureate to reach the age of 100 |
| 45% | VOYAGER | 7 | First spacecraft to reach Uranus and Neptune |
| 44% | STLOUIS | 7 | First U.S. city to host the Olympics |
| 44% | GLENN | 5 | First U.S. astronaut to circle the earth |
| 44% | STLOUIS | 7 | First U.S. city to host the Olympic Games |
| 44% | STL | 3 | First U.S. city to host the Olympics (Abbr.) |
| 44% | STL | 3 | First U.S. city to host the Olympic Games |
| 44% | AMUNDSEN | 8 | First explorer to reach the South Pole |
| 43% | TYLER | 5 | First U.S. vice president to ascend to the presidency |
| 43% | THEM | 4 | The first to mix? Not us |
| 43% | THEM | 4 | The first to sew? Not us |
| 43% | THEM | 4 | The first to join? Not us |
| 42% | THEM | 4 | The first to turn up? Not us |
| 42% | ANNEMURRAY | 10 | First Canadian female solo artist to reach No. 1 on the U.S. Billboard Hot 100 |
| 42% | LETITGO | 7 | First Disney song to reach the top 5 on Billboard in the 21st century |
| 41% | NYRANGERS | 9 | First U.S. team to win the N.H.L. Stanley Cup (1928) |
| 41% | MANHATTAN | 9 | The US project to develop the first atom bomb |
| 41% | TITANIC | 7 | The first film to reach the billion-dollar mark |
| 41% | ASHE | 4 | First Black man to win the U.S. Open |
| 41% | SHIRLEYCHISHOLM | 15 | First Black woman elected to the U.S. Congress |
| 41% | DEL | 3 | First state admitted to the US: Abbr. |
| 41% | NHL | 3 | It first expanded to the US in 1924 |