States › Maryland › St. Mary's County › ZIP 20628
ZIP code
ZIP 20628
St. Mary's County · Lexington Park, MD · Maryland
FHFA notes: The FHFA HPI is a broad measure of the movement of single-family house prices. The FHFA HPI is a weighted, repeat-sales index, meaning that it measures average price changes in repeat sales or refinancings on the same properties. FHFA describes its ZIP code indexes as developmental: they may be revised as new data arrive or methods change, and the index does not give a dollar value for any home.
St. Mary's County, Maryland ZIP 20628 has 17 years of index history. Since 2003 the FHFA index has moved from 100 to 141, a change of +40.6%. FHFA's most recent value for this area is for 2021, so every span here ends in 2021.
Over the ten years to 2021 the index rose +2.6%, about +0.3% a year: well below St. Mary's County (+21.2%), well below Maryland (+32.3%) and well below the national index (+58.3%). The change over 2020–2021 was +9.9%.
From its 2005 peak the index fell −22.3% to a 2014 low and has not yet regained that peak.
Building activity is measured at county level: St. Mary's County authorised 201 housing units in the 12 months to August 2026, 1.7 per 1,000 residents, 86% of them single-family.
Same span, five levels
| Change in the FHFA index | ZIP 20628 | St. Mary's County | Lexington Park area | Maryland | United States |
|---|---|---|---|---|---|
| 1 year (2020–2021) | +9.9% | +8.7% | +8.9% | +9.5% | +11.6% |
| 5 years (2016–2021) | +18.3% | +21.5% | +21.2% | +22.3% | +33.4% |
| 10 years (2011–2021) | +2.6% | +21.2% | +24.2% | +32.3% | +58.3% |
| 20 years (2001–2021) | — | +81.2% | +83.6% | +95.0% | +83.8% |
| Since 2000 | — | +91.9% | +94.7% | +110.4% | +96.1% |
| Since 2003 | +40.6% | +59.8% | +58.4% | +64.8% | +66.8% |
| 10-year annualised | +0.3% | +1.9% | +2.2% | +2.8% | +4.7% |
| 20-year annualised | — | +3.0% | +3.1% | +3.4% | +3.1% |
Every column uses FHFA's annual all-transactions index family and the same start and end years, so the figures are directly comparable. A dash means the level has no index for that span.
Decade by decade
| Decade | Change | United States | |
|---|---|---|---|
| 2010s (2010–2020) | −3.8% | +35.5% | |
| 2020s so far (2020–2021) | +9.9% | +11.6% |
FHFA reports each index with a value of 100 in its base period, the first year the area has enough transactions (2003 here). A decade's change is the index at the end of the decade divided by the index at the start, so it does not depend on the base year; the United States column covers the same years. Decades before 2003 are not shown.
Peak-to-low declines
Falls of 5% or more from a previous high in the annual index, and the year the earlier peak was regained.
| Peak | Low | Decline | Peak regained |
|---|---|---|---|
| 2005 | 2014 | −22.3% | not by 2021 |
Building permits in St. Mary's County
Permits are reported by county and by permit-issuing place, not by ZIP code. Housing units authorised in St. Mary's County, latest 12 months.
Housing units authorised in St. Mary's County by month, Sep 2025 to Aug 2026single-family2+ unit buildings
Full permit history and every city in St. Mary's County
Other ZIP codes in St. Mary's County
Ranked by ten-year change in the FHFA index.
| ZIP | 1 year | 10 years | Since 2000 | Index through |
|---|---|---|---|---|
| 20634 | +18.9% | +89.1% | +169.9% | 2025 |
| 20650 | +4.8% | +65.4% | +162.6% | 2025 |
| 20659 | +10.7% | +65.0% | +161.9% | 2025 |
| 20653 | +8.0% | +64.4% | +147.8% | 2025 |
| 20690 | +23.2% | +55.2% | — | 2022 |
| 20619 | −3.1% | +54.7% | +130.9% | 2025 |
| 20684 | — | +52.3% | — | 2024 |
| 20674 | +6.1% | +51.4% | — | 2024 |
| 20621 | +23.9% | +50.4% | — | 2022 |
| 20636 | +2.7% | +44.3% | +124.1% | 2025 |
| 20624 | +17.0% | +35.1% | — | 2022 |
| 20609 | +5.1% | +27.6% | — | 2022 |
All 17 ZIP codes in St. Mary's County
Questions and answers
How much have home values in ZIP 20628 risen over 10 years?
The FHFA house price index for 20628 rose +2.6% between 2011 and 2021, about +0.3% a year compounded. Over five years the change was +18.3% and over one year +9.9%.
How does 20628 compare with St. Mary's County?
Over the same ten years to 2021, St. Mary's County rose +21.2%, Maryland +32.3% and the United States +58.3%, against +2.6% for the ZIP.
What happened to prices in 20628 after 2007?
The index peaked in 2005, fell −22.3% to its 2014 low and had not regained that peak by 2021. Nationally the fall was −21.3% from 2007 to 2012.
How many homes are being built in 20628?
Building permits are published by place and county, not by ZIP. St. Mary's County authorised 201 housing units in the 12 months to August 2026, −32.6% on the previous 12 months. The county page lists permits by month and by city.
Where does the index for this ZIP come from?
From the Federal Housing Finance Agency's annual five-digit ZIP code house price index (all-transactions), last updated March 31, 2026. FHFA labels the ZIP-level indexes developmental: they are calibrated on appraisal values and sales prices for mortgages bought or guaranteed by Fannie Mae and Freddie Mac, and may be revised. The index tracks price changes for the same homes over time; it does not give a dollar value for any home.
Provenance
Index: Federal Housing Finance Agency, annual house price index for five-digit ZIP codes (all-transactions, developmental), last updated March 31, 2026, values 2003–2021, public domain. County, state and national comparison series are FHFA's annual indexes for those levels from the same release. ZIP to county assignment uses the Census Bureau's 2020 ZCTA-to-county relationship file (largest land share); county to metro uses OMB's July 2023 delineations. Permits: Census Bureau Building Permits Survey through August 2026. Errors in processing are corrected at the next build; see corrections. FHFA HPI datasets.