Harbor Island, South Carolina Demographics & Population 2026

A note before these figures: with a population of 303, Harbor Island's ACS estimates come from a small number of survey responses and carry wide margins of error. Individual percentages below — particularly rates that round to 0% or 100% — are approximations, not precise measurements. See data.census.gov for the published margins of error.

Population Overview

Harbor Island is a small community located in South Carolina, within Beaufort County. The total population is 303. It ranks as the 380th most populous out of 474 Census-designated places in South Carolina.

Age Demographics

The median age in Harbor Island is 69.6 years. This is 73% higher than the state median of 40.2 years. 11.9% of residents are 75 or older, suggesting a significant retirement-age population with implications for healthcare services and senior housing.

Economy, Income & Housing

The median household income in Harbor Island is $105,425. This is 52% higher than the state median of $69,324. It is also 31% higher than the national median of $80,734. The poverty rate stands at 9.2%. This is 34% lower than the state poverty rate of 14.1%. The survey records no unemployed residents in Harbor Island, which reflects the size of the sample rather than a labor market without joblessness. The median home value is $366,100. Housing costs are 41% higher than the state median of $259,000. The home-value-to-income ratio is 3.5x. 93.7% of occupied housing units are owner-occupied. This homeownership rate is 30% higher than the state average of 71.9%.

Race & Ethnicity

Harbor Island has a predominantly White (non-Hispanic) population, comprising 97.4% of all residents. The White (non-Hispanic) population is significantly higher than the state average (97.4% vs 61.9%).

Education

83.3% of residents aged 25 and older hold a bachelor's degree or higher. This places Harbor Island in the top 10% of all cities in the state for educational attainment. This is 159% higher than the state rate of 32.1%. Nationally, 35.7% of adults hold at least a bachelor's degree. No surveyed resident aged 25 or older reported leaving school before earning a high school diploma, though a rate of exactly 100% reflects the limits of a small sample. Notably, 39.0% of adults hold a graduate or professional degree, indicating a highly educated workforce.

Data Sources & Methodology

All demographic data for Harbor Island, South Carolina is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against South Carolina state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 474 Census-designated places in South Carolina. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.