Marsh symbol
Small blue tufts, like clumps of grass, spread over an area mark a marsh or swamp on a topographic map.
How to read it
The USGS symbol sheet has symbols for marsh or swamp, submerged marsh or swamp, and wooded marsh or swamp, drawn in the blue it uses for water; the wooded kind sits on the green it uses for vegetation. Natural Resources Canada’s legend has one symbol for marsh, muskeg or swamp, and prints swamps and marshes in blue with other water features.
Also searched as: blue grass tufts on a map, marsh or swamp, swamp symbol, wetland symbol.
These pages describe what each symbol on a map shows. They are not navigation instructions: the map’s own legend says what each of its symbols means, and symbols differ between map series and editions.
Differences by country
On Ordnance Survey Explorer maps the marsh symbol covers marsh, reeds or saltings.
Look-alikes
Blue dashes and dots in a line are an Intermittent stream symbol.
Read next
- Next in Topographic map symbolsBuilding symbolA small black square on a topographic map is a building, usually a house. Larger buildings are drawn to their actual shape.
- The same shape in UML diagram symbolsLifelineA box with a dashed line running down from it, in a sequence diagram, is a lifeline: one participant in the interaction, with time running down the page. A narrow bar on the line marks a stretch when that participant is busy carrying out a call.
More topographic map symbols
The same shape elsewhere
Browse symbols drawn with lines.
Sources
- Topographic Map Symbols, USGS General Information Product (first posted 2005), U.S. Geological Survey, Submerged areas and bogs
- Toporama Legend, Edition 1.2, 2013 (after the NTS 1:50,000 standards and specifications), Natural Resources Canada, Legend
- Topographic Maps: The Basics, Centre for Topographic Information guide, Natural Resources Canada, What do the colours mean?
- OS Explorer map legend (1:25 000), Generic legend, version 2022-09, Ordnance Survey, Vegetation
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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