How much wetland is left?

The U.S. Fish and Wildlife Service's National Wetlands Inventory for Ohio, mapped from aerial photographs: freshwater marshes (emergent), swamps (forested and shrub) and ponds, clipped to each ZIP, with open lakes and river channels left out. Ohio drained about 90 percent of its original wetlands, so what remains is concentrated in the northwest's Great Black Swamp remnants, the Lake Erie marshes and the glacial kettles of the northeast. Mapped wetlands carry federal and state permit requirements for filling, and they are where the water table sits at the surface. Ohio EPA's vernal pool screening, high-quality wetland list and mitigation sites are noted. Ohio EPA's own wetland assessments add the nearest studied wetland with its ORAM and plant community scores. Where USGS topographic maps marked marsh or swamp, the card gives those acres too.

1,233 of 1,233 ZIPs have data; median 1%.

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Legend

Under 1% of the land · 492 1 to 3% · 435 3 to 7% · 210 7 to 15% · 76 15% or more wetland · 20

Map of Ohio by Wetlands

Highest and lowest

Source

USFWS National Wetlands Inventory, Ohio geodatabase (imagery mostly 2004 to 2007, Lake Erie basin 2021), freshwater wetlands and ponds clipped to each ZIP (lakes and rivers excluded); Ohio EPA potential high-quality vernal pools, high-quality wetland sites and stream and wetland mitigation sites; Ohio EPA Wetland Ecology Group sampling sites with ORAM and VIBI scores; Ohio EPA hydro/Wetlands_USGSTopoMaps (wetland symbols digitized from USGS 7.5-minute topographic maps), clipped to the ZIP

USFWS wetlands inventory · Ohio EPA GIS services

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Quick answers

Which Ohio ZIP code has the highest share of wetland?

ZIP code 44064 (Montville Township and Montville, 34%) ranks highest, followed by 44450 (Greene Township and North Bloomfield, 27%) and 43733 (Valley Township and Derwent, 27%). The U.S.

Which Ohio ZIP code has the lowest share of wetland?

ZIP code 43032 (Brown Township and Kilbourne, 0%) ranks lowest, followed by 43047 (Wayne Township and Mingo, 0%) and 43117 (Darby Township and Derby, 0%). The U.S.

What is the typical share of wetland in Ohio?

Across Ohio ZIP codes: 1,233 of 1,233 ZIPs have data; median 1%. The U.S.

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Cracked Buckeye, "Wetlands", https://crackedbuckeye.com/topics/wetlands/, built 2026-10-31, accessed [date].

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