Counties with the highest water share
The percentage of each county equivalent’s published square-mile total that is water. A high percentage reflects water assigned to the statistical geography, not necessarily lakes entirely enclosed by its land boundary.
Ranks 1–100
3,222 county equivalents · page 1 of 33
What this part of the ranking shows
This page runs from Culebra Municipio, Puerto Rico at 93.101% water to St. John the Baptist Parish, Louisiana at 47.691% water. The 100 entries represent 24 state-level jurisdictions. Michigan has the most entries on this page (20).
Culebra Municipio leads with 93.1% water, followed by Keweenaw County at 90.9%. A small land area can produce a high water percentage even when another county contains more square miles of water. Use the total-area column alongside water share to distinguish the two.
Assigned water includes the Census water measurement for that jurisdiction. This percentage does not measure flood risk, access to water, or the share of land occupied by lakes.
| Rank | County / equivalent | State | Land mi² | Total mi² | Water share |
|---|---|---|---|---|---|
| 1 | Culebra Municipio | Puerto Rico | 11.6 | 168.8 | 93.1% |
| 2 | Keweenaw County | Michigan | 540.1 | 5,966.3 | 90.9% |
| 3 | Leelanau County | Michigan | 347.2 | 2,532.2 | 86.3% |
| 4 | Nantucket County | Massachusetts | 46.2 | 303.7 | 84.8% |
| 5 | St. Bernard Parish | Louisiana | 377.5 | 2,155.2 | 82.5% |
| 6 | Alger County | Michigan | 915 | 5,047.7 | 81.9% |
| 7 | Ceiba Municipio | Puerto Rico | 29 | 158.8 | 81.7% |
| 8 | Monroe County | Florida | 983 | 5,289.6 | 81.4% |
| 9 | Vieques Municipio | Puerto Rico | 50.8 | 264 | 80.8% |
| 10 | Poquoson city | Virginia | 15.4 | 78.5 | 80.4% |
| 11 | San Francisco County | California | 46.7 | 231.9 | 79.9% |
| 12 | Milwaukee County | Wisconsin | 241.5 | 1,189.5 | 79.7% |
| 13 | Door County | Wisconsin | 481.9 | 2,370.2 | 79.7% |
| 14 | Ozaukee County | Wisconsin | 233 | 1,116.2 | 79.1% |
| 15 | Dukes County | Massachusetts | 103.2 | 491 | 79% |
| 16 | Kalawao County | Hawaii | 12 | 52.8 | 77.3% |
| 17 | Lake County | Ohio | 229.4 | 979.3 | 76.6% |
| 18 | Dare County | North Carolina | 383.2 | 1,541.7 | 75.1% |
| 19 | Presque Isle County | Michigan | 658.7 | 2,572.8 | 74.4% |
| 20 | Rincón Municipio | Puerto Rico | 14.3 | 54.4 | 73.7% |
| 21 | Northampton County | Virginia | 211.7 | 795.3 | 73.4% |
| 22 | Honolulu County | Hawaii | 600.8 | 2,166.2 | 72.3% |
| 23 | San Juan County | Washington | 173.9 | 620.8 | 72% |
| 24 | Mayagüez Municipio | Puerto Rico | 77.6 | 274.1 | 71.7% |
| 25 | Fajardo Municipio | Puerto Rico | 29.9 | 105.3 | 71.6% |
| 26 | Iosco County | Michigan | 549.5 | 1,890.1 | 70.9% |
| 27 | Loíza Municipio | Puerto Rico | 19.4 | 65.6 | 70.5% |
| 28 | Charlevoix County | Michigan | 416.3 | 1,390.4 | 70.1% |
| 29 | Barnstable County | Massachusetts | 394.2 | 1,305.5 | 69.8% |
| 30 | Plaquemines Parish | Louisiana | 780.6 | 2,567.2 | 69.6% |
| 31 | Aleutians West Census Area | Alaska | 4,387.3 | 14,116.5 | 68.9% |
| 32 | Kewaunee County | Wisconsin | 342.5 | 1,084.3 | 68.4% |
| 33 | Pinellas County | Florida | 273.8 | 860.3 | 68.2% |
| 34 | Knox County | Maine | 364.9 | 1,132.3 | 67.8% |
| 35 | Lake County | Illinois | 443.7 | 1,368.3 | 67.6% |
| 36 | Newport County | Rhode Island | 102.4 | 313.6 | 67.3% |
| 37 | Alpena County | Michigan | 571.9 | 1,694.9 | 66.3% |
| 38 | Mathews County | Virginia | 85.9 | 252 | 65.9% |
| 39 | Accomack County | Virginia | 449.3 | 1,310 | 65.7% |
| 40 | Muskegon County | Michigan | 503.9 | 1,460 | 65.5% |
| 41 | Ottawa County | Michigan | 563.5 | 1,631.4 | 65.5% |
| 42 | Ontonagon County | Michigan | 1,311 | 3,740.4 | 65% |
| 43 | Berrien County | Michigan | 567.8 | 1,581.5 | 64.1% |
| 44 | Kenosha County | Wisconsin | 271.8 | 754 | 63.9% |
| 45 | Cuyahoga County | Ohio | 457.2 | 1,245.5 | 63.3% |
| 46 | Benzie County | Michigan | 319.7 | 859.6 | 62.8% |
| 47 | Alcona County | Michigan | 674.7 | 1,790.6 | 62.3% |
| 48 | Hampton city | Virginia | 51.5 | 136.3 | 62.2% |
| 49 | Carteret County | North Carolina | 507.6 | 1,330.4 | 61.8% |
| 50 | Franklin County | Florida | 545 | 1,421.6 | 61.7% |
| 51 | Suffolk County | New York | 910.9 | 2,373.3 | 61.6% |
| 52 | Huron County | Michigan | 835.9 | 2,136.8 | 60.9% |
| 53 | Manitowoc County | Wisconsin | 589.3 | 1,494.1 | 60.6% |
| 54 | Cabo Rojo Municipio | Puerto Rico | 70.4 | 177.4 | 60.3% |
| 55 | Mason County | Michigan | 495 | 1,242.3 | 60.2% |
| 56 | Erie County | Ohio | 251.3 | 625.8 | 59.8% |
| 57 | Sheboygan County | Wisconsin | 511.5 | 1,271.2 | 59.8% |
| 58 | Island County | Washington | 208.7 | 517.3 | 59.7% |
| 59 | Cape May County | New Jersey | 251.5 | 620.3 | 59.5% |
| 60 | Oceana County | Michigan | 538.1 | 1,306 | 58.8% |
| 61 | Hyde County | North Carolina | 612.3 | 1,459 | 58% |
| 62 | Racine County | Wisconsin | 332.6 | 792.1 | 58% |
| 63 | Arroyo Municipio | Puerto Rico | 15 | 35.7 | 57.9% |
| 64 | Grand Isle County | Vermont | 81.8 | 193.3 | 57.7% |
| 65 | Manistee County | Michigan | 542.3 | 1,280.7 | 57.7% |
| 66 | Dorado Municipio | Puerto Rico | 23.1 | 53.8 | 57% |
| 67 | Galveston County | Texas | 379.4 | 873.9 | 56.6% |
| 68 | Cook County | Minnesota | 1,452.6 | 3,339.8 | 56.5% |
| 69 | Ottawa County | Ohio | 254.7 | 585.1 | 56.5% |
| 70 | Wayne County | New York | 603.8 | 1,383.1 | 56.3% |
| 71 | Santa Isabel Municipio | Puerto Rico | 34.1 | 77 | 55.7% |
| 72 | Allegan County | Michigan | 825.4 | 1,833.3 | 55% |
| 73 | Ashland County | Wisconsin | 1,045 | 2,292.4 | 54.4% |
| 74 | Niagara County | New York | 522.3 | 1,139.6 | 54.2% |
| 75 | Aleutians East Borough | Alaska | 6,985.2 | 15,016.2 | 53.5% |
| 76 | Guánica Municipio | Puerto Rico | 37.1 | 79.5 | 53.3% |
| 77 | Jefferson Parish | Louisiana | 300.9 | 642 | 53.1% |
| 78 | St. Mary's County | Maryland | 358.6 | 764.3 | 53.1% |
| 79 | Luce County | Michigan | 899.1 | 1,912.5 | 53% |
| 80 | Aransas County | Texas | 252.3 | 528 | 52.2% |
| 81 | Orleans County | New York | 391.3 | 817.4 | 52.1% |
| 82 | Monroe County | New York | 657 | 1,366.7 | 51.9% |
| 83 | Prince of Wales-Hyder Census Area | Alaska | 5,268.2 | 10,914.9 | 51.7% |
| 84 | Aguadilla Municipio | Puerto Rico | 36.5 | 75.6 | 51.6% |
| 85 | Maui County | Hawaii | 1,161.5 | 2,398.3 | 51.6% |
| 86 | Suffolk County | Massachusetts | 58.3 | 120.2 | 51.5% |
| 87 | Orleans Parish | Louisiana | 169.6 | 349.8 | 51.5% |
| 88 | Mackinac County | Michigan | 1,021.9 | 2,100.6 | 51.4% |
| 89 | York County | Virginia | 104.7 | 215 | 51.3% |
| 90 | Kauai County | Hawaii | 619.8 | 1,266.3 | 51.1% |
| 91 | Calhoun County | Texas | 506.9 | 1,032.7 | 50.9% |
| 92 | Virginia Beach city | Virginia | 244.7 | 497.5 | 50.8% |
| 93 | Currituck County | North Carolina | 261.9 | 526.4 | 50.2% |
| 94 | St. Mary Parish | Louisiana | 558.5 | 1,119.7 | 50.1% |
| 95 | Davis County | Utah | 324.9 | 635.4 | 48.9% |
| 96 | Erie County | Pennsylvania | 799 | 1,558.1 | 48.7% |
| 97 | Ashtabula County | Ohio | 702.4 | 1,368.2 | 48.7% |
| 98 | Lee County | Florida | 781.2 | 1,514.8 | 48.4% |
| 99 | Bay County | Florida | 758.6 | 1,466.7 | 48.3% |
| 100 | St. John the Baptist Parish | Louisiana | 214.5 | 410 | 47.7% |
Read the differences behind ranks 1–100
The median water share among these 100 entries is 61.641 %. The first and last entries span 45.411 percentage points. This median describes the entries on this page, not the full national dataset. Pagination is a browsing boundary, not a distinct geographic region.
A percentage-point gap is the subtraction of two shares. It differs from a relative percentage change, and it does not tell you the difference in water square miles. Check each profile’s original water measurement if absolute water extent is your question.
Where the entries on this page are located
- Michigan20 entries · 20% of this page
- Puerto Rico13 entries · 13% of this page
- Wisconsin9 entries · 9% of this page
- Virginia7 entries · 7% of this page
- Louisiana6 entries · 6% of this page
- Florida5 entries · 5% of this page
The remaining 18 jurisdictions contribute 40 entries. The list above shows the six most represented, with alphabetical ordering when counts tie.
These counts describe representation in this slice of the ranking. They do not measure a state’s share of national land or population. Compare the first and last county equivalents on this page to inspect land, water, and total area separately.
Read the geographic explanation behind this ranking, or return to the ranking overview for the national distribution and guidance on selecting a measurement.
Land rankings use original ALAND square meters; total-area rankings use ALAND + AWATER. Exact ties use ascending GEOID. Displayed square-mile values are rounded. Read the methodology.