Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
Locations and reports
Radon Levels in Harrison County, Mississippi
EPA puts Harrison County in Zone 3, its lowest radon zone. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Nearest county
4.4%
Mobile County, 57 miles
- Mobile
- 4.4%
Share at 4+ pCi/L, 45 tests, 2006 to 2015
Ground above low
None
8.1 pts below MS
- Harrison
- 0.0%
- MS
- 8.1%
Share of land USGS rates moderate or high potential
Tests reported
0
None published
A home here needs its own test
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for Harrison County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
Harrison County, At a glance
Harrison County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 98% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
No CDC test figures here
CDC has published no radon test figures for Harrison County. Mobile County, AL, 57 miles away, is the nearest county with a figure over the 2006 to 2015 laboratory totals.
Harrison County, Compared
Harrison County radon figures, compared
Calculated by Radon411CDC publishes no radon test figure for Harrison County, and none for any other Mississippi county: its counts over the 2006 to 2015 laboratory totals cover 2,669 counties elsewhere in the country. Across every county in the country with a figure (2,669), 36.3% of reported tests reached that level; no Mississippi county contributes to that pool.
The nearest counties with a figure are Mobile County, AL (57 miles away) at 4.4%, Tangipahoa Parish, LA (77 miles away) at 0.0% and Jefferson Parish, LA (78 miles away) at 1.5%.
EPA's 1993 map puts Harrison County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 98% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Harrison County, Geology
The ground under Harrison County
PredictedUSGS's geologic map puts all of Harrison County's mapped land in one class: low radon potential. The map puts 74.8% of Harrison County in the area it calls Pine Hills and 23.1% in Coastal Pine Meadows. USGS gives both a radon index of 6, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Pine Hills | Sand, sandstone, bentonitic clay, quartzite, gravel, tuff, and siltstone. | Low | 6 | 74.8% |
| Coastal Pine Meadows | Alluvial deltas consisting of gravel, sand and clay. | Low | 6 | 23.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Harrison County beside the ground around it
Across Mississippi 0.1% of the land is rated high; none of Harrison County's is. None of the 4 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Harrison County, Local resources
Radon testing and mitigation in Harrison County
- Mississippi Radon ProgramMississippi Radon Program, run by Mississippi State Department of Health, answers questions about testing, mitigation and the rules in Mississippi.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- See the Mississippi directoryNo professionals are listed in Mississippi yet. The state program can point you to registered testers and mitigators.
What Mississippi's program says
- Phone
- 1-800-626-7739
What it means
Harrison County, Questions
Questions about radon in Harrison County
Are radon levels high in Harrison County?
No CDC testing statistics are published here for Harrison County, Mississippi yet. Of the 8 nearest counties with a figure, within 208 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 12.8%.
Which counties border Harrison County?
Harrison County borders 4 counties: Stone County, Hancock County, Jackson County and Pearl River County.
Products
Harrison County, Products
Testing a home in Harrison County
No CDC figure names Harrison County; the nearest county with one, Mobile County, AL (57 miles away), reported 4.4% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Harrison County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-1011 rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Harrison County, Bordering counties
Counties bordering Harrison County
Calculated by Radon411counties bordering Harrison County: 1 of 4
Harrison County, Cities and towns
Cities and towns in Harrison County
The Census Bureau estimates 217,136 residents in Harrison County for July 1, 2025, 8,315 more than in 2020 (+4.0%). That works out to 379 people per square mile of land. Its largest town, Gulfport, has 76,506 residents, 35.2% of the total. Together its 5 incorporated places hold 74.8% of those residents; the other 25.2% live outside any of them.
From Gulfport to Pass Christian, CDC publishes no figure by town: each reads Harrison County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Gulfport | 76,506 | +5.0% | 35.2% |
| Biloxi | 48,516 | −1.8% | 22.3% |
| Long Beach | 17,309 | +3.0% | 8.0% |
| D'Iberville | 13,557 | +6.6% | 6.2% |
| Pass Christian | 6,459 | +12.3% | 3.0% |
5 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Harrison County, Homes
Homes in Harrison County
Of Harrison County's 93,505 homes, 65% are detached houses, against 69% across Mississippi; 18% are in buildings of five or more homes. Half of its homes were built before 1993, close to Mississippi's 1986: 11% date from before 1960 and 40% from 2000 or later. 61% of occupied homes are lived in by their owner (Mississippi: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Harrison County | Mississippi |
|---|---|---|
| Housing units | 93,505 | 1,332,811 |
| Detached houses | 65% | 69% |
| In buildings of 5 or more | 18% | 9% |
| Mobile homes | 8% | 15% |
| Built before 1960 | 11% | 15% |
| Built since 2000 | 40% | 28% |
| Middle year built | 1993 | 1986 |
| Owner-occupied | 61% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.