Discover Maryland's Herps

Field Guide to Maryland's Turtles (Order Testudines)

Family Emydidae

Northern Map Turtle
Graptemys geographica

Photo of Northern Map Turtle courtesy of Jim Harding
Photo of Northern Map Turtle courtesy of Jim Harding

Size

3 ½ inches – 11 inches

Appearance

  • The northern map turtle is so named because the yellowish orange thin lines on the olive carapace (top shell) resemble contour lines on a topographic map.

  • The carapace is moderately keeled and the rear edge of the shell is serrated.

  • The plastron (bottom shell) is yellow with no patterns.

  • There is one yellow spot behind each eye.

  • The “lips” look full due to the broad light-colored jaw.

  • Females are much larger than males.

    •

    Photo of Northern Map Turtle courtesy of Jay Killian
    Photo of Northern Map Turtle
    courtesy of Jay Killian

    Habitat

    Prefers the deep or shallow parts of slow-moving rivers, large streams and lakes. Needs plenty of vegetation, muddy bottoms and abundant basking sites.

    How to Find

    This turtle is rarely seen away from water. In the spring, males can be seen swimming in front of females as part of the courtship dance. Use binoculars to survey basking sites along slow rivers. If you get too close, the turtles will drop back into the water.

    Photo of Habitat for Northern Map Turtle courtesy of Sara Weglein
    Photo of Habitat for Northern Map Turtle
    courtesy of Sara Weglein

    Distribution in Maryland

    Found only in Harford and Cecil Counties along the Susquehanna River.
     

    Maryland Distribution Map for Northern Map Turtle

     

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    Maryland Amphibian
    and Reptile Atlas Project

    "A Joint Project of the Natural History Society of Maryland, Inc. and the Maryland Department of Natural Resources"

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    The Maryland Herpetology Field Guide is a cooperative effort of the MD Natural Heritage Program and the MD Biological Stream Survey within the Department of Natural Resources and their partners. We wish to thank all who contributed field records, text, and photographs, as well as support throughout its development.