| Riley | Casey | |
|---|---|---|
| Meaning | Valiant; rye clearing | Vigilant in war |
| Origin | Irish | irish |
| Gender | Unisex | Unisex |
| Pronunciation | RY-lee | KAY-see |
| Syllables | 2 | 2 |
| First appeared | 1923 | 1888 |
| Peak year | 2016 (7,159) | 1990 (4,134) |
| In 2025 | 4,441 | 1,072 |
| Trend | Steady | Steady |
Source: US Social Security Administration.
| Decade | Riley | Casey |
|---|---|---|
| 2020s | 29,219 | 5,474 |
| 2010s | 56,150 | 5,582 |
| 2000s | 45,533 | 12,261 |
| 1990s | 10,234 | 29,253 |
| 1980s | 680 | 35,968 |
| 1970s | 72 | 18,987 |
| 1960s | 11 | 4,723 |
| 1950s | 18 | 2,656 |
| 1940s | 21 | 571 |
| 1930s | 11 | 277 |
| 1920s | 11 | 347 |
| 1910s | 0 | 444 |
| 1900s | 0 | 89 |
| 1890s | 0 | 37 |
| 1880s | 0 | 6 |
Riley has two strands: the Irish Ó Raghallaigh, linked to “valiant” or “courageous,” and an English place name meaning “rye clearing.”
From the Irish surname Ó Cathasaigh, whose byname 'cathasach' derives from 'cath' (battle) and is usually glossed 'vigilant, watchful' (in war); a secondary reading is 'noisy'.
Riley is more popular than Casey today: about 4,441 US babies were given the name Riley in 2025, compared with 1,072 named Casey.
Riley means Valiant; rye clearing (Irish origin), while Casey means Vigilant in war (irish origin).
In US records, Riley first appears in 1923 and Casey in 1888, so Casey has the longer recorded history.