How Many People Are Named Marilou?
An estimated 1,588 people in the United States have the first name Marilou. It is almost exclusively a female name. The average bearer is 64 years old, and Marilou peaked in popularity in 1948 with 90 births that year.
Below you will find a full statistical profile of Marilou as a first name in the United States, including gender data, a year-by-year popularity timeline going back to 1880, a decade breakdown, and state-by-state birth registrations. You can also check how many people share the full name Marilou paired with any surname.
Estimated Living Americans
1,588
About 1 in 215,840 people in the U.S.
Rarity
Rare
Predicted Gender
Female
100.0% confidence
Average Age
64
years old
Peak Year
1948
90 births
Total Registered
3,231
since 1880
Gender Distribution for Marilou
Marilou is almost exclusively a female name. Out of 3,231 total births registered, 100.0% were female.
Marilou as a female name
Ranked #11,730 in 2024
8 female births in 2024
Peak: 1948 (90 births)
Marilou: Popularity Over Time
SSA records for Marilou span from the 1910s to the 2020s, covering 12 decades of naming data. The most popular decade for this name was the 1940s, when 729 babies were registered. Marilou has declined significantly from its peak in the 1940s. Recent registrations are a fraction of what they were at the name's height.
Marilou by Decade
How has Marilou tracked across different eras? The table below groups all SSA birth registrations into 10-year periods, with separate male and female counts. The colored bar shows each decade's share relative to the peak.
Marilou by State
Birth registrations for Marilou span all 18 states and territories in the SSA database. The highest counts are in California, Ohio, Illinois. The lowest are in Kentucky, Kansas, Connecticut. On average, about 74 Marilous were registered per state.
Marilou + Last Name Combinations
How many people share a full name with Marilou as the first name? Click a combination below to see the estimate, or search any pairing.
Names Similar to Marilou
Other first names starting with M with a similar number of bearers.
Marilou: Questions and Answers
How many people in the U.S. are named Marilou?
We estimate approximately 1,588 people named Marilou are alive in the United States today. This is based on SSA birth records from 1880 to 2024, adjusted for mortality using CDC life tables. About 1 in 215,840 Americans share this first name.
Is Marilou a common name?
Marilou is classified as "Rare" and is more popular than 92.7% of all first names in the SSA database. A total of 3,231 births have been registered with this name since 1880.
When was Marilou most popular?
Marilou reached peak popularity in 1948, when 90 babies were given this name. The average age of a living person named Marilou is approximately 64 years old, reflecting when the name was most commonly given.
Is Marilou a female name?
Marilou is predominantly female. 100.0% of people with this name are female. See the gender breakdown above for full details.
How many Marilou Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Marilou Smith, Marilou Johnson, Marilou Williams. You can also search any combination on our homepage.
Where does this data come from?
Our estimates use Social Security Administration birth records (1880 to 2024), adjusted for survival using CDC 2023 life tables broken down by sex. The U.S. population figure (342,754,338) is from the Census Bureau's July 2025 estimate. Full methodology.
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