Map Symbol Legend for topographic maps

Since a map is a reduced representation of the real world, map symbols are used to represent real objects. Without symbols, we wouldn't have maps.
Both shapes and colors can be used for symbols on maps. A small circle may mean a point of interest, with a brown circle meaning recreation, red circle meaning services, and green circle meaning rest stop. Colors may cover larger areas of a map, such as green representing forested land and blue representing waterways.
To ensure that a person can correctly read a map, a Map Legend is a key to all the symbols used on a map. It is like a dictionary so you can understand the meaning of what the map represents.
Here are some common symbols:

TOPOGRAPHIC CONTOURS (land elevation)
Index number written on line
Intermediate between Index lines
Supplementary added to flat areas to show measurements
Depression such as volcano top or crater (little dashes are called hachures)
Cut; Fill roadway leveling terrain
VEGETATION
Woodland trees at least 6feet tall
Scrub low brush
Orchard planted vegetation
Vineyard cultivated vines
Mangrove dense, tropical trees
SURFACE FEATURES
Levee
Sand or mud area, dunes or shifting sand
Intricate surface area
Gravel beach or glacial moraine
Tailings pond
MINES AND CAVES
Quarry or open pit mine
Gravel, sand, clay, or borrow pit
Mine tunnel or cave entrance
Prospect; mine shaft
Mine dump
Mine tailings
GLACIERS AND PERMANENT SNOWFIELDS
Limit blue denotes coverage
Form lines Show shape, not elevation
BUILDINGS AND RELATED FEATURES
Building
School; church
Built-up Area
Racetrack
Airport
Landing strip
Well (other than water); windmill
Tanks
Covered reservoir
Gaging station
Landmark object (feature as labeled)
Campground; picnic area
Cemetery: small; large
ROADS AND RELATED FEATURES
Primary highway
Secondary highway
Light duty road
Unimproved road
Trail
Dual highway
Dual highway with median strip
Road under construction
Underpass; overpass
Bridge
Drawbridge
Tunnel
RAILROADS AND RELATED FEATURES
Standard gauge single track; station
Standard gauge multiple track
Abandoned
Under construction
Narrow gauge single track
Narrow gauge multiple track
Railroad in street
Juxtaposition
Roundhouse and turntable
TRANSMISSION LINES AND PIPELINES
Power transmission line: pole; tower
Telephone line
Aboveground oil or gas pipeline
Underground oil or gas pipeline
BOUNDARIES
National
State or territorial
County
Civil township
Incorporated city
Park, reservation, or monument
Small Park
LAND SURVEY SYSTEMS
*U.S. Public Land Survey System*
Township or range line
Section Line
Found section corner; found closing corner
Witness corner; meander corner
*Other land surveys*
Township or range line
Section line
Land grant or mining claim; monument
Fence line
CONTROL DATA AND MONUMENTS
*Horizontal control*
Third order or better, permanent mark
With third order or better elevation
Check spot elevation
Coincident with section corner
Unmonumented*
*Vertical control*
Third order or better, with tablet
Third order or better, recoverable mark
Bench mark found at section corner
Spot elevation
*Boundary monument*
With tablet
Without tablet
With number and elevation
U.S. mineral or location monument
RIVERS, LAKES, AND CANALS
Intermittent stream
Intermittent river
Disappearing stream
Perennial stream
Perennial river
Small falls; small rapids
Large falls; large rapids
Masonry dam
Dam with rock
Dam carrying road
Perennial lake; Intermittent lake or pond
Dry lake
Narrow wash
Wide wash
Canal, flume, or aquaduct with lock
Elevated aquaduct, flume or conduit
Aquaduct tunnel
Well or spring; spring or seep
SUBMERGED AREAS AND BOGS
Marsh or swamp
Submerged marsh or swamp
Wooded marsh or swamp
Submerged wooded marsh or swamp
Rice field
Land subject to inundation
MARINE SHORELINE
Approximate mean high water
Indefinite or unsurveyed
BATHYMETRIC FEATURES (water depth)
Area exposed at mean low tide; sounding datum
Channel
Offshore oil or gas: well; platform
Sunken rock
BATHYMETRIC CONTOURS
Index
Intermediate
Supplementary