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