County outline
Where St. Johns County is located
Area breakdown
Land accounts for 73.1% of St. Johns County’s measured area and water for 26.9%. Its combined area converts to 2,127.8 square kilometers or approximately 525,780 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 600.66 | 1,555.702 | 384,422.4 |
| Water | 220.872 | 572.056 | 141,358.1 |
| Total | 821.532 | 2,127.758 | 525,780.5 |
How St. Johns County compares
By original Census land area, St. Johns County ranks #44 of 67 in Florida and #1623 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.862 times the Florida county-equivalent median of 696.5 square miles. It accounts for 1.1% of the combined county land area in the state.
See the complete Florida ranking · What counts as a county equivalent?
What stands out about St. Johns County?
St. Johns County has more land than 1,599 of the other 3,221 county equivalents in the dataset.
A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.
Does including water change its rank?
Using land plus water places St. Johns County at #1,130 nationally by total area, 493 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.
Its water share is 26.9%, compared with a national county-equivalent median of 1.2% — 25.7 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.
Closest positions in the national land ranking
These entries sit immediately beside St. Johns County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1622 | Honolulu County, Hawaii | 600.8 | Compare |
| #1623 | St. Johns County, Florida | 600.7 | This county |
| #1624 | Pike County, Arkansas | 600.3 | Compare |
Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.
Representative coordinates
The Census internal point is 29.881393, -81.388281. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,555,701,129 m²; AWATER: 572,055,461 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How many acres of land are in St. Johns County?
The land measurement converts to approximately 384,422 acres. Including water, total area is approximately 525,780 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.