Maryland counties by area
Official, comparable measurements for 24 counties and county equivalents.
- 80.9–276.9 mi²
- 319.4–371.7 mi²
- 374.4–447.6 mi²
- 457.8–493.1 mi²
- 540.8–660.7 mi²
- 44–107 per mi²
- 116–286 per mi²
- 309–395 per mi²
- 443–1,417 per mi²
- 1,455–7,042 per mi²
Understanding Maryland’s county areas
The land-area range runs from Baltimore city at 80.9 mi² to Frederick County at 660.7 mi². The largest has 8.2 times the land area of the smallest and accounts for 6.8% of the combined county land in Maryland. Compare with every state’s largest county.
The median county-equivalent land area is 418.5 mi², below the national median of 604.5 mi². The median describes the middle of the county size distribution; it does not describe how people or development are distributed. A state with a few very large counties can have a much smaller median than its largest entry suggests.
Where water changes the picture
Dorchester County has the most assigned water area, at 442.2 mi². St. Mary's County has the highest water share, with water making up 53.1% of its total area. Water area and water percentage answer different questions: the first measures an amount, while the second measures the mix of land and water.
Across all 24 entries, water accounts for 21.7% of the combined total area. This is calculated from the summed land and water measurements, rather than averaging county percentages, which would give each small and large county equal weight.
Where people live
An estimated 6,265,347 people lived in Maryland on July 1, 2025 (+1.4% since 2020), or 1.8% of the national total in this dataset. Montgomery County is the most populous county equivalent, with 1,074,582 residents — 17.2% of the state. The largest by land, Frederick County, has 302,883.
Across the state there are 645 people per square mile of land. County densities range from 7,042 in Baltimore city to 44 in Garrett County; the median county equivalent has 335. Switch the map above to density to see where the state’s population concentrates.
Compare the largest and smallest county equivalents in Maryland to see land, water, and total area on the same scale.
These calculations use the 2026 Census county records listed below. County-equivalent boundaries vary between states; area alone does not measure population, density, or usable land. See coverage and calculation rules.
Complete area table
Sorted from largest to smallest land area.
| # | County / equivalent | Land | Water | Water share | Population | Per mi² |
|---|---|---|---|---|---|---|
| 1 | Frederick CountyGEOID 24021 | 660.7 mi² | 6.8 mi² | 1% | 302,883 | 458 |
| 2 | Garrett CountyGEOID 24023 | 649.1 mi² | 8.7 mi² | 1.3% | 28,370 | 44 |
| 3 | Baltimore CountyGEOID 24005 | 598.4 mi² | 83.4 mi² | 12.2% | 847,650 | 1,417 |
| 4 | Dorchester CountyGEOID 24019 | 540.8 mi² | 442.2 mi² | 45% | 33,628 | 62 |
| 5 | Montgomery CountyGEOID 24031 | 493.1 mi² | 13.8 mi² | 2.7% | 1,074,582 | 2,179 |
| 6 | Prince George's CountyGEOID 24033 | 482.6 mi² | 16.2 mi² | 3.3% | 970,374 | 2,011 |
| 7 | Worcester CountyGEOID 24047 | 468.3 mi² | 226.6 mi² | 32.6% | 54,459 | 116 |
| 8 | Charles CountyGEOID 24017 | 457.8 mi² | 185.1 mi² | 28.8% | 176,593 | 386 |
| 9 | Washington CountyGEOID 24043 | 457.8 mi² | 9.6 mi² | 2% | 157,731 | 345 |
| 10 | Carroll CountyGEOID 24013 | 447.6 mi² | 5.1 mi² | 1.1% | 176,677 | 395 |
| 11 | Harford CountyGEOID 24025 | 437.1 mi² | 89.5 mi² | 17% | 266,446 | 610 |
| 12 | Allegany CountyGEOID 24001 | 422.2 mi² | 5.7 mi² | 1.3% | 66,848 | 158 |
| 13 | Anne Arundel CountyGEOID 24003 | 414.8 mi² | 173 mi² | 29.4% | 603,380 | 1,455 |
| 14 | Wicomico CountyGEOID 24045 | 374.4 mi² | 25.8 mi² | 6.4% | 106,899 | 286 |
| 15 | Queen Anne's CountyGEOID 24035 | 371.7 mi² | 139 mi² | 27.2% | 54,448 | 146 |
| 16 | St. Mary's CountyGEOID 24037 | 358.6 mi² | 405.7 mi² | 53.1% | 116,692 | 325 |
| 17 | Cecil CountyGEOID 24015 | 346.3 mi² | 71.5 mi² | 17.1% | 107,131 | 309 |
| 18 | Somerset CountyGEOID 24039 | 319.7 mi² | 290.6 mi² | 47.6% | 24,973 | 78 |
| 19 | Caroline CountyGEOID 24011 | 319.4 mi² | 6.5 mi² | 2% | 34,116 | 107 |
| 20 | Kent CountyGEOID 24029 | 276.9 mi² | 136.5 mi² | 33% | 19,565 | 71 |
| 21 | Talbot CountyGEOID 24041 | 268.6 mi² | 208.3 mi² | 43.7% | 38,238 | 142 |
| 22 | Howard CountyGEOID 24027 | 251 mi² | 2.4 mi² | 1% | 339,183 | 1,352 |
| 23 | Calvert CountyGEOID 24009 | 213.2 mi² | 131.9 mi² | 38.2% | 94,484 | 443 |
| 24 | Baltimore cityGEOID 24510 | 80.9 mi² | 11.1 mi² | 12.1% | 569,997 | 7,042 |