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Mercer County, Pennsylvania

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Low overall risk
26th of 67highest risk in Pennsylvania
$34Mexpected losses a year
11federal declarations
1 in 1000homes with flood insurance
Photo: U.S. Geological Survey, public domain

Mercer County, Pennsylvania has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 78% of US counties. It ranks 26th of 67 counties in Pennsylvania. The costliest hazards here are inland flooding, tornadoes and strong wind. FEMA estimates about $34 million a year in expected losses, or roughly $309 per resident. Since 1972 it has been included in 11 federal disaster or emergency declarations for natural events (7 major disasters). The most recent was in October 2012 (Hurricane Sandy). Fewer than 1 in 100 homes here carry federal flood insurance (62 policies). Since 1978, federal flood insurance has paid about $880,000 on 120 claims here.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Mercer County

$29.1 million a yearExpected losses. Damaging events about 3 times a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.
$1.3 million a yearExpected losses. Damaging events about once every 4 years.
  • Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
  • Turn on emergency alerts on your phone and keep a weather radio.

Strong wind

Moderate
$980,505 a yearExpected losses. Damaging events about 2 times a year.
  • Secure outdoor furniture and trash bins before storms.
  • Have trees near the house checked.
HazardRatingScoreExpected loss a year
Inland floodingModerate87.9
$29M
TornadoLow55.3
$1M
Strong windModerate74.0
$981K
LightningHigh87.3
$926K
HailModerate75.9
$647K
HurricaneLow64.8
$306K
EarthquakeVery Low51.5
$269K
Cold waveVery Low23.2
$255K
Winter weatherModerate77.9
$168K
Heat waveVery Low28.4
$110K
Ice stormLow42.2
$53K
WildfireVery Low36.4
$19K
LandslideVery Low43.1
$737

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively moderate and community resilience is relatively high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Mercer County. 2020s bar runs to November 2026.

By type

Flood3
Hurricane3
Snowstorm2
Severe Storm2
Tornado1

Most recent

Oct 29, 2012Hurricane SandyEmergency
Sep 10, 2005Hurricane KatrinaEmergency
Sep 19, 2004Severe Storms and Flooding Associated With Tropical Depression FrancesMajor disaster
Sep 19, 2004Tropical Depression IvanMajor disaster
Aug 23, 2003Severe Storms, Tornadoes, and FloodingMajor disaster
Jan 21, 1996Severe Storms and FloodingMajor disaster
Mar 16, 1993Severe Snowfall & Winter StormEmergency
Jun 3, 1985Severe Storms, High Winds & TornadoesMajor disaster
Jun 15, 1981Severe Storms & FloodingMajor disaster
Jan 29, 1977SnowstormsEmergency
Show all 11
Jun 23, 1972Tropical Storm AgnesMajor disaster

Pennsylvania also had 7 statewide declarations that did not name single counties.

Storm history since 1954

Tornado risk by county ›

The National Weather Service has logged 818 storm reports in Mercer County since 1954, with 9 deaths and 95 injuries and about $38.1 million in reported damage. The strongest on record here was an F5 tornado on May 31, 1985.

25tornadoes
160hail reports, largest 2.75 inches
528damaging thunderstorm winds
101floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 31, 1985F5–60 / 8
May 31, 1985F5–0 / 0
May 31, 1985F4–5 / 0
May 2, 1972F3–0 / 0
Nov 10, 2002F2Sharpsville19 / 1

Most damaging storms

DateTypeNearDamage
May 31, 1985Tornado–$25M
Oct 3, 1986Tornado–$3M
Nov 10, 2002TornadoSharpsville$1M
Oct 6, 2024Thunderstorm WindDeleware Grove$1M
Apr 28, 2002TornadoMercer$750K
May 24, 1995Thunderstorm WindMercer$375K

Source: NOAA Storm Events Database, county-based reports through Jul 21, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Hurricanes and tropical storms

Hurricane risk by county ›

Since 1955, 0 hurricanes and 1 tropical storm have passed within 65 miles of the center of Mercer County, 1 of them since 1950. The strongest was Tropical Storm Connie (1955), with top winds near 50 mph about 64 miles away.

0hurricanes
0major hurricanes (Category 3+)
1tropical storms
1955most recent: Connie

Strongest storms nearby

DateStormStrengthClosest
Aug 13, 1955ConnieTropical storm, 50 mph64 mi

Most recent storms

DateStormStrengthClosest
Aug 13, 1955ConnieTropical storm, 50 mph64 mi

Source: NOAA National Hurricane Center best-track records (HURDAT2), 1851 to 2025 for the Atlantic and 1949 to 2025 for the eastern Pacific. A storm counts if its track passed within 65 miles of the county's center while it was a tropical storm or hurricane. Strength is the storm's top sustained wind at that point, not the wind measured in the county. Older storms over the open sea were sometimes missed.

Flood insurance in Mercer County

Check your address flood zone ›
0.1%of homes have federal flood insurance (62 policies)
8.7%of homes in mapped high-risk flood zones are insured
$880,001paid on 120 flood claims since 1978
2004costliest year, with $279,066 paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Mercer County

$164,000median home value (Pennsylvania $254,500, US $332,700)
1963median year homes were built (Pennsylvania 1965, US 1980)
73%of homes built before 1980, before many modern wind, quake and flood building rules
7%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 50,930 housing units.

Compare in Pennsylvania

All 67 ›
Largest countiesOverall riskTop hazard
Philadelphia CountyVery HighInland flooding
Allegheny CountyHighInland flooding
Montgomery CountyHighInland flooding
Bucks CountyHighInland flooding
Delaware CountyModerateInland flooding
Lancaster CountyHighInland flooding
Chester CountyModerateInland flooding
York CountyModerateInland flooding

Neighboring counties

CountyOverall riskDeclarations
Mahoning County, OHModerate10
Trumbull County, OHModerate9
Butler CountyLow9
Lawrence CountyLow10
Crawford CountyLow13
Venango CountyLow13

Common questions about Mercer County

What is the biggest natural hazard in Mercer County?

Inland flooding has the highest expected yearly losses in Mercer County, about $29.1 million a year in FEMA's estimate. Tornado is second at $1.3 million.

How many federal disasters has Mercer County had?

Mercer County has been included in 11 federal disaster or emergency declarations for natural events since 1972, including 7 major disasters. The most recent was Hurricane Sandy in October 2012.

Is Mercer County a high-risk place to live?

Its overall rating is Relatively Low, 26th highest of 67 in Pennsylvania. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Mercer County?

Standard home insurance does not cover flooding. About 1 in 1000 homes in Mercer County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Mercer County had?

NOAA records list 25 tornadoes in Mercer County since 1950. The strongest was an F5 tornado on May 31, 1985. The weather service has also logged 160 hail reports and 101 floods here.

How many hurricanes have hit Mercer County?

NOAA's hurricane records show 0 hurricanes and 1 tropical storm passing within 65 miles of the center of Mercer County. The strongest was Tropical Storm Connie (1955), with winds near 50 mph.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.