riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Middlesex County Disaster Risk

Middlesex County, New Jersey

FEMA Risk Rating

Relatively High

National Percentile

98th

of 3,144 counties

State Rank

#2

of 21 (1 = highest risk)

Flood Risk

99th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively High

Higher than 99% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 80% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively High

Higher than 94% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively High

Higher than 96% of US counties

Hurricane

Tropical cyclone and hurricane risk

Moderate

Higher than 93% of US counties

Risk Overview

About Natural Disaster Risk in Middlesex County, New Jersey

Middlesex County ranks among riskiest nationally

Middlesex County scores 97.77 out of 100 for composite disaster risk, making it the highest-scoring county in this dataset and well above national and state averages. This exceptional risk reflects multiple significant hazards converging across a densely populated region.

New Jersey's single riskiest county

Middlesex County ranks as the most at-risk county statewide with a composite score of 97.77, outpacing the state average of 90.81 by nearly 7 points. No other New Jersey county exceeds this risk level.

Riskier than all adjacent counties

Middlesex County (97.77) substantially exceeds Hudson County (97.23), Mercer County (95.36), and Morris County (92.88). Its combination of coastal exposure, urbanization, and infrastructure density amplifies risk across virtually all hazard categories.

Floods, tornadoes, and earthquakes

Middlesex County faces the nation's highest flood risks at 98.86, driven by extensive waterfront exposure, coastal geography, and stormwater challenges. Tornado risk (94.50) is exceptionally high, earthquake risk scores 96.25, and wildfire risk (79.71) reflects significant forest and grassland coverage throughout the county.

Make disaster insurance non-negotiable

Middlesex County residents must secure flood insurance immediately—this is the single most important step, given the county's 98.86 flood risk score. Layer in earthquake, tornado, and wind coverage, and develop a multi-hazard emergency plan with your household.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Middlesex County

Top Hazards by Exposure

  1. #1
    FloodPrepare
    99th percentile
  2. #2
    EarthquakePrepare
    96th percentile
  3. #3
    TornadoPrepare
    94th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Risk Advisory: Middlesex County

Risk Verdict

FEMA's National Risk Index places Middlesex County at the 98th percentile nationally — in the high-risk bracket for U.S. counties. Residents should prioritize a formal household emergency plan, including evacuation routes, insurance review, and a well-stocked emergency kit.

Hazard Breakdown

Flood risk is Middlesex County's dominant natural hazard, ranked at the 99th percentile nationally under FEMA's National Risk Index. Earthquake ranks second at the 96th percentile nationally. Additional tracked hazards include tornado (94th percentile), hurricane (93th percentile), wildfire (80th percentile).

Preparedness Context

Flood risk is Middlesex County's top hazard at the 99th percentile nationally. Households in or near designated flood zones face elevated financial exposure; flood insurance typically requires a 30-day waiting period before it takes effect, so applying before the season is advisable. Alongside flooding, earthquake exposure at the 96th percentile means households benefit from a multi-hazard preparedness plan rather than focusing on flood alone. Households across Middlesex County should identify the nearest community shelter and keep a basic emergency kit — water, non-perishable food, medications, flashlight, and battery radio — in a location easy to grab quickly.

Regional Context

Middlesex County is 7.0 composite risk points above the New Jersey average, indicating that residents face greater natural hazard exposure than most of their in-state neighbors.

Is your household prepared for Middlesex County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Middlesex County, NJ?
Middlesex County has a FEMA National Risk Index rating of Relatively High, placing it in the 98th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Middlesex County?
Middlesex County is evaluated for five major natural hazard types: flooding (99th percentile), earthquake (96th percentile), tornado (94th percentile), hurricane (93th percentile), wildfire (80th percentile). The highest-risk hazard is flooding at the 99th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Middlesex County risk compare to the New Jersey average?
Middlesex County's composite risk percentile is 98th, compared to the New Jersey state average of 91th percentile. The state's overall risk rating is Relatively Moderate. This means Middlesex County faces higher natural disaster risk than the typical county in New Jersey.
Is Middlesex County at risk for flooding?
Yes, Middlesex County's flooding risk is at the 99th percentile nationally. This places it in the top quartile for this hazard type.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is Middlesex County higher risk than average?
Middlesex County's composite risk score of 98th percentile is above the New Jersey state average of 91th percentile. This elevated risk is driven by flooding exposure (99th percentile), along with earthquake and tornado and hurricane and wildfire risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.
By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.