ZIP 21757 vs ZIP 21778

This side-by-side compares ZIP 21757 (Keymar, MD) and ZIP 21778 (Rocky Ridge, MD) using the same Census ACS 5-Year table fields for both — no averages swapped in, no national proxies. ZIP 21757 has a population of 3,036 at 31 people per square mile, while ZIP 21778 has 1,094 at 24 per square mile. That difference in population size and density alone reshapes how every other metric should be interpreted — a higher-income ZIP with 1,200 residents behaves very differently from one with 45,000.

On income and education, ZIP 21757 reports a median household income of $100,500 against $76,458 in ZIP 21778, with per-capita income of $46,390 vs $54,798. The share of adults holding a bachelor's degree or higher is 29.5% in 21757 and 27.0% in 21778. Poverty rate reads 1.7% vs 0.9%, and unemployment 3.2% vs 6.5% — these four fields alone drive most of the difference in the scorecard grades you will see for each ZIP.

Housing separates these two ZIPs further: median home value sits at $466,100 in 21757 versus $382,100 in 21778, with median rent of $1,408 and — per month respectively. Homeownership rate is 82.4% vs 81.3%. When reading the comparison table below, focus on paired metrics rather than single winners — a ZIP with lower home values and lower income is not strictly "worse" if rent-to-income ratios and commute times land in the same zone. Every value is pulled from the exact same ACS table so the two columns are genuinely comparable.