Buying in New Castle County, Delaware

New Castle County at a glance

New Castle County is one of 3 counties and county-equivalents in Delaware. Its county seat is Wilmington. County government publishes its offices and parcel tools online. Official county website. Its 2024 Census Bureau population estimate is 588,093 across 426 square miles of land — about 1,380 people per square mile. In the FBI's 2024 reported-crime file, agencies here reported 13,139 offenses — 22.34 per 1,000 residents; the breakdown is below.

Records to check before you buy in New Castle County

• Property record card — the New Castle County assessor / appraisal office. Pull the parcel's assessed-value history, exemption status, and last sale. This is the file your future tax bill is calculated from, and it shows whether the current owner is enjoying exemptions you will not inherit. County government sits in Wilmington; the official county website is the reliable route to the parcel search and the office directory.
• Deeds & liens — the New Castle County recorder / land-records office. Read the deed chain, open liens, easements, and plat maps — the file a listing never mentions.
• Official flood determination. Check the exact parcel on FEMA's National Flood Hazard Layer — not the listing site's licensed model. Zone boundaries cut through streets; the house next door can be in a different zone. New Castle County is the primary county for 29 ZIP codes in the Census Bureau's ZIP-to-county crosswalk — and zone lines ignore every one of them.
• The county's reported-crime record. In the FBI's 2024 file, agencies in New Castle County reported 13,139 offenses — 22.34 per 1,000 residents; the largest single category was larceny-theft (8,195). The crime section below sets that beside the Delaware county median.
• Registry check. Run the address through Delaware Sex Offender Central Registry (Delaware State Police, State Bureau of Identification) and note the counts within a mile — then check again the week you close.
• Permits & code history — the New Castle building department. Open permits, expired permits, and code cases tell you whether the renovation in the photos was ever inspected. County permitting is run out of Wilmington.
• School assignment — the district office, not the listing. Only the district's own boundary lookup confirms which school an address is actually zoned for.

County list, land area and population: U.S. Census Bureau (population: 2024 PEP estimate). County seat and official website: Wikidata (CC0), checked 2026-11-04. Flood determinations: FEMA. Registry: Delaware.

Reported crime in New Castle County — FBI 2024

Agencies in New Castle County reported 13,139 offenses to the FBI in 2024 — 2,156 violent and 10,983 property offenses. That works out to a reported-crime rate of 22.34 per 1,000 residents (violent 366.6, property 1867.6 per 100,000).

The largest reported categories were larceny-theft (8,195), motor vehicle theft (1,668) and aggravated assault (1,656).

Coverage: 19 of 19 law-enforcement agencies assigned to this county reported at least one month of 2024 offense data to the FBI; 18 reported all 12 months. Counts are reported offenses only (FBI Return A / Arson master files), assigned whole to each agency's primary county; they are not adjusted for non-reporting agencies.

These are offenses reported to law enforcement — not convictions, and not a verdict on any street or address. A CurbFacts report pairs this county record with the ZIP-level picture for the specific address you are buying.

Source: FBI Crime Data Explorer, UCR Return A + Arson master files, data year 2024 (pulled 2026-11-04).

The Delaware rules that apply in New Castle County

Traps researched for Delaware buyers: Mandatory radon disclosure is separate from the main form; Decades-old assessments were just replaced.

Read the full Delaware guide — disclosure standard, tax math, registry and flood

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