Casidy
Of Irish and Gaelic origin, meaning "curly-haired".
Name Census estimates that about 338 living Americans carry the first name Casidy. The name is used almost exclusively for girls. The average person named Casidy today is around 26 years old, and the year with the single highest number of Casidy births was 2001 (26 babies).
This page is the full Name Census profile for Casidy. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
People living today
338
~ 1 in 1,014,066 Americans
Peak year
2001
26 babies that year
Average age
26
years old
2016 SSA rank
#13,172
Tracked since 1980
Popularity
Casidy: popularity over time
The SSA tracks Casidy from the 1980s through to the 2010s, spanning 4 decades of birth certificate data. The biggest single decade for the name was the 2000s, with 145 total registrations. Although the numbers have come down from the 2000s peak, Casidy remains solidly in use and shows no sign of disappearing from maternity wards.
Babies born per year
Decades
Casidy by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Casidy during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Origin
Meaning and history of Casidy
The given name Casidy has its origins in the Irish Gaelic language, with roots dating back to the medieval period. The name is believed to be a variant spelling of the Irish name Caisidhe, which means "watchful" or "vigilant." This name was particularly common in regions like Ulster and Connacht, where the Irish language and culture thrived.
During the Middle Ages, the name Caisidhe was often bestowed upon individuals who displayed qualities of watchfulness and vigilance, traits highly valued in those times. It was not uncommon for names to reflect personal characteristics or virtues in various cultures.
While there are no definitive records of the name appearing in ancient texts or religious scriptures, some historians suggest that variations of the name may have been used in early Irish folklore and legends, reflecting the cultural significance of watchfulness and protection.
One of the earliest recorded instances of the name Casidy can be traced back to the 16th century, when it was documented in Irish genealogical records. In this context, the name was often associated with families of noble or warrior lineage, further reinforcing its connection with vigilance and guardianship.
Throughout history, several notable individuals have borne the name Casidy. A few examples include:
1. Casidy O'Donnell (c. 1560-1628), an Irish chieftain and military leader who played a significant role in the Nine Years' War against English forces in Ulster.
2. Casidy Fitzgerald (1770-1835), an Irish-born American soldier who fought in the War of 1812 and later became a prominent figure in the early settlement of Kentucky.
3. Casidy O'Connor (1832-1904), an Irish-American author and journalist known for her works on Irish culture and folklore.
4. Casidy Brennan (1875-1948), an Irish-born American businessman and philanthropist who made significant contributions to education and healthcare initiatives in New York City.
5. Casidy MacLean (1911-1989), a Scottish-Canadian artist and sculptor renowned for her work in modernist styles and her contributions to the arts community in Vancouver, Canada.
While the name Casidy may have evolved in spelling over time, its Irish roots and associations with watchfulness and vigilance have remained a constant theme throughout its history, making it a unique and culturally significant name.
People
Casidy + last name combinations
How many people share a full name with Casidy as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with C
Other first names starting with C with a similar number of bearers.
FAQ
Casidy: questions and answers
How many people in the U.S. are named Casidy?
Name Census puts the figure at roughly 338 living Americans. We arrive at this by taking every SSA birth registration for Casidy going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 1,014,066 US residents.
Is Casidy a common name?
We classify Casidy as "Very Rare". It ranks above 80.5% of all first names in the SSA dataset by living bearers. Across the full history of the data, 346 babies have been registered with this name.
When was Casidy most popular?
The single biggest year for Casidy was 2001, when 26 babies received the name. The fact that the average living Casidy is about 26 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
Is Casidy a female name?
Yes, 100.0% of people registered as Casidy in the SSA data are female. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.