St. Mary's County · Maryland
ZIP code 20684
- Population
- 825
- Median income
- $176,938
- Median home
- $375,500
- Sales tax
- 6%
ZCTA residents
Household, past 12 months
Owner-occupied value
Maryland state rate
Quick answer
ZIP 20684 sits in St. Mary's County, Maryland and is home to 825 people. Median household income is $176,938, the median home is worth $375,500 and median gross rent is —. 94.6% of households own their home, and purchases are taxed at 6% (Maryland state rate).
- County
- St. Mary's County
- State
- Maryland (MD)
- Area codes
- Not published
- Metro area
- Outside covered metros
FIPS 24037
477 ZIPs covered
No NANPA match for this ZIP
Rate jurisdiction used for tax
The numbers for 20684
American Community Survey 2019-2023 ACS 5-year estimates for this ZCTA.
- Population
- 825ZIP 20684 residents
- Median household income
- $176,938Past 12 months, inflation adjusted
- Median home value
- $375,500Owner-occupied units
- Median gross rent
- —Rent plus utilities, monthly
- Median age
- 44.5 yrsAll residents
- Homeownership rate
- 94.6%Owner-occupied households
Sales tax in 20684
What a purchase inside this ZIP costs at checkout.
Maryland levies 6% statewide with no local add-ons. Check the county page for the local component before you quote a price.
Affordability in this ZIP
Derived from the Census medians above — indicative, not an offer.
A rent burden above 30% is the federal threshold for cost-burdened households, and a price-to-income multiple above 4× is generally considered a stretched housing market. The mortgage figure is principal and interest only — taxes, insurance and HOA dues are extra.
How 20684 compares
ZIP 20684 against the median ZIP in St. Mary's County and across Maryland.
| Measure | ZIP 20684 | County median | State median | vs state |
|---|---|---|---|---|
| Median household income | $176,938 | $117,501 | $104,338 | +70% |
| Median home value | $375,500 | $405,350 | $401,000 | -6% |
| Median gross rent | — | $1,648 | $1,600 | — |
| Population | 825 | 926 | 4,995 | -83% |
Medians are computed across the 26 ZIP areas in St. Mary's County and the 477 ZIP areas in Maryland.
Statewide rank
Where this ZIP places among all 477 Maryland ZIP areas.
- Income
- #37
- Home value
- #239
- Population
- #363
richer than 91% of 428 state ZIPs
above 44% of 425 state ZIPs
larger than 24% of 477 state ZIPs
Comparable ZIP codes
Maryland ZIP areas with almost the same household income.
Nearby ZIP codes
Other ZIP codes filed under St. Mary's County.
ZIP 20684 questions
Common questions about this ZIP code.
- Where is ZIP code 20684?
- ZIP 20684 lies mostly in St. Mary's County, Maryland. County assignment follows the largest share of land area, so a ZIP straddling a county line is filed under its dominant county.
- What sales tax do I pay in 20684?
- Maryland charges 6% statewide.
- Is 20684 expensive to live in?
- Median rent runs — a month, and the median home is worth $375,500 — -6% against the typical Maryland ZIP.
- Is a ZCTA the same as a postal ZIP code?
- Not exactly. The Census builds ZIP Code Tabulation Areas from the ZIP codes of addresses inside each census block, so a ZCTA can differ slightly from the USPS delivery route of the same number, and PO-box-only ZIPs have no ZCTA at all.
Keep going
Related pages for this area.
Sources & transparency
- US Census Bureau, ACS 2019-2023 5-year estimates — 2019-2023 ACS 5-year — population, income, housing
- Census 2020 ZCTA-to-county relationship file — County assignment by largest land-area overlap
- Comptroller of Maryland — Sales tax rates and local add-ons
Last reviewed December 2024. Figures are published for reference and can change; verify with the source agency before filing or contracting. How we build and check this data.