Based on a census of the literature, herbaria specimens, and confirmed sightings, C. pensylvanica is found in Manitoba, Ontario, and Quebec in Canada; and in the United States it is most widely distributed in Connecticut, Illinois, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, Pennsylvania, mainland Rhode Island, Virginia and Wisconsin.

It is also found in Arkansas, Kentucky, Maine, Maryland and the District of Columbia, New York, West Virginia, and Vermont.

[2] Pennsylvania sedge produces leaves up to 2 ft (0.6 m) long and 1 to 3 mm (0.04 to 0.12 in) wide that become arching at maturity.

[4] In order to assess the dynamics of three stress factors on Carex pensylvanica development on forest beds, researchers conducted an experiment consisting of even-aged silvicultural systems.

[8] In hardwood forests in northern Minnesota, Carex pensylvanica were found to have a greater dominance in comparison to other understory plant species in areas where invasive earthworms were present for two decades or more.