St. Lucie County, FL population age distribution
A complete breakdown of St. Lucie County's age demographics from 0 to 85 years, distributed across 18 age groups is listed in the table below.
Age Group | Population | % of Total Population |
---|---|---|
Under 5 years | 16,111 | 4.96% |
5 to 9 years | 16,351 | 5.04% |
10 to 14 years | 20,679 | 6.37% |
15 to 19 years | 18,103 | 5.58% |
20 to 24 years | 16,398 | 5.05% |
25 to 29 years | 18,609 | 5.73% |
30 to 34 years | 18,620 | 5.74% |
35 to 39 years | 17,461 | 5.38% |
40 to 44 years | 18,672 | 5.75% |
45 to 49 years | 19,073 | 5.88% |
50 to 54 years | 20,641 | 6.36% |
55 to 59 years | 22,717 | 7% |
60 to 64 years | 23,352 | 7.19% |
65 to 69 years | 22,118 | 6.81% |
70 to 74 years | 20,967 | 6.46% |
75 to 79 years | 15,720 | 4.84% |
80 to 84 years | 10,753 | 3.31% |
85 years and over | 8,254 | 2.54% |
TABLE OF CONTENTS
St. Lucie County, FL population by age group
Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The largest age group in St. Lucie County, FL was for the group of age 60-64 years with a population of 23,352 (7.19%), according to the 2021 American Community Survey.
At the same time, the smallest age group in St. Lucie County, FL was the 85+ years with a population of 8,254 (2.54%).
St. Lucie County, FL population by age cohort
To better understand the age distribution of St. Lucie County, FL's population, we divided it into the following 3 cohorts:
- Children : Under the age of 18 years
- Adults (working population): Between the age of 18 and 64 years
- Seniors: 65 years and above

Here's the population for each of the three cohorts.
Age Group | Population | % of Total Population |
---|---|---|
Under 18 years | 64,663 | 19.92% |
18 to 64 years | 182,124 | 56.11% |
85 years and over | 77,812 | 23.97% |
Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:
- St. Lucie County's population under 18 was 19.92%, compared to the 22.51% nationwide.
- St. Lucie County's working population (between 18 and 64) was 56.11%, compared to 61.45% nationwide.
- St. Lucie County's elderly or the senior population (over 65 age) was 23.97% as compared to 16.04% nationwide.
St. Lucie County, FL population pyramid
Population pyramid for St. Lucie County, FL is charted below using the estimates from U.S. Census Bureau's American Community Survey 5-Year estimates. A wide base suggests population increase, narrow base indicates declining birth rates.
Key stats from our analysis of the St. Lucie County's population pyramid:
- Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for St. Lucie County, FL, is 27.4.
- Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for St. Lucie County, FL, is 40.2.
- Total dependency ratio for St. Lucie County, FL is 67.6.
- Potential support ratio, which is the number of youth (working age population) per elderly, for St. Lucie County, FL is 2.5.

Here's the St. Lucie County, FL's male and female population across different age groups:
Age Group | Population(Male) | Population(Female) | Total Population |
---|---|---|---|
Under 5 years | 8,251 | 7,860 | 16,111 |
5 to 9 years | 8,169 | 8,182 | 16,351 |
10 to 14 years | 10,814 | 9,865 | 20,679 |
15 to 19 years | 9,480 | 8,623 | 18,103 |
20 to 24 years | 8,393 | 8,005 | 16,398 |
25 to 29 years | 9,502 | 9,107 | 18,609 |
30 to 34 years | 9,318 | 9,302 | 18,620 |
35 to 39 years | 8,241 | 9,220 | 17,461 |
40 to 44 years | 9,465 | 9,207 | 18,672 |
45 to 49 years | 9,179 | 9,894 | 19,073 |
50 to 54 years | 10,069 | 10,572 | 20,641 |
55 to 59 years | 10,541 | 12,176 | 22,717 |
60 to 64 years | 11,361 | 11,991 | 23,352 |
65 to 69 years | 11,091 | 11,027 | 22,118 |
70 to 74 years | 9,235 | 11,732 | 20,967 |
75 to 79 years | 6,999 | 8,721 | 15,720 |
80 to 84 years | 5,350 | 5,403 | 10,753 |
85 years and over | 3,925 | 4,329 | 8,254 |
Things to know
What is the population of St. Lucie County, FL under 18?
St. Lucie County's population under the age of 18 is 64,663, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 19.92% of the total resident population of St. Lucie County, FL.
What is the aging population in St. Lucie County, FL?
St. Lucie County's population aged 65 years and above was 77,812. As per the U.S. Census Bureau's American Community Survey, this population is 23.97% of the entire population.
References
- U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates