The northern leopard frog is found across Canada from Prince Edward Island to southern British Columbia and it is also widely distributed in the United States.

Northern leopard frogs are usually green, but they may also be brown or grey, with an unmarked milky-white underside. The spots are round or oval in outline with distinct light borders, much as those of a leopard are.

The northern leopard frog breeds in lakes, ponds and marshes in the early spring, but it is primarily a frog of meadows and other grassy areas in the summer. In late autumn, the frogs return to the water where they usually remain more-or-less dormant on the bottom in winter.

Tadpoles of these frogs generally transform in July and August into froglets that are slightly less than 2.5 cm (1 in.) long. They first breed at an age when they have reached a length of about 5 cm (2 in.). Adult leopard frogs can grow to 10 cm (4 in.) in body length.