Counties · MD
Counties in Maryland
4 Maryland counties live on zipradar today, covering 5 ZIP codes across Annapolis, Baltimore, Chevy Chase, and Rockville. County-level data anchors property tax (county assessor), deed activity (county recorder), and the EPA Map of Radon Zones.
MD
Anne Arundel County
1 ZIP code
MD
Baltimore (city)
1 ZIP code
MD
Baltimore City
1 ZIP code
MD
Montgomery County (MD)
2 ZIP codes
What zipradar surfaces at the Maryland county level
County governments — not states or the federal government — own four of the most decision-relevant neighborhood-data layers. zipradar federates each from its authoritative public source, refreshed on the cadence each agency publishes.
- Property tax
- Maryland county assessors publish parcel-level millage rates and assessed values. zipradar federates the county-by-county tax structure so a buyer can compare effective tax burden across Maryland's 4 counties. Annual reassessment cadence; check each county for the most recent reassessment year.
- Deed activity
- County recorders log every property transfer. zipradar surfaces aggregated deed activity (count of recent transfers, median sale price ranges) at the ZIP level, never owner names or PII. Daily filings; published with a 1-2 day recorder lag.
- Radon zones
- The EPA Map of Radon Zones classifies every US county into Zone 1 (highest risk), Zone 2 (moderate), or Zone 3 (lowest). The 1993 baseline is overlaid with state-level radon survey data when published. zipradar shows the zone designation for each Maryland county.
- Sex offender registry
- County and state registries are linked in real time via the National Sex Offender Public Website (NSOPW). zipradar deep-links to the official registry — never caches personal records — so privacy statutes are honored at the source.
Other Maryland data layers
Eight more dimensions sit above the county level — water quality, flood zones, wildfire risk, air quality, crime, schools, lead pipes, and zoning. State-wide rollups for Maryland live at /state/md/. Per-ZIP detail lives on each individual /zip/[code] page.
For the full source list, refresh cadence, and limitations of every dataset, see methodology. For plain-language explainers on what each dimension actually measures, see learn.