7/8-1 1/8" (22-28 mm). Above, FW bright copper or brass-colored with dark spots and margin; HW dark brown
with copper margin. Undersides mostly grayish with black dots; FW has some orange, HW has prominent submarginal orange band.
Female Bronze Copper is similarly patterned but larger. No other copper, except the duskier Bog Copper, is as small as the American.
Egg pale green with pronounced ribbing. Mature caterpillar downy, either green with rose side markings, or dull rose with yellowish side markings; overwinters as chrysalis. Host plants
are sheep sorrel (Rumex acetosella) and curly dock (R. crispus) in eastern lowlands, and mountain sorrel (Oxyria digyna) in arctic and alpine habitats.
Lowland form has multiple broods: 2 broods in North and 4 or more in South from April-October. Arctic and alpine forms have 1 brood in August.
Lowland form in waste places, pastures, yards, and old fields. Arctic and alpine forms found above treeline on barren ground, talus slopes, and fell-fields.
Lowland form widespread over East from Nova Scotia and Gaspe south and east to North Dakota, NE. Kansas, Arkansas, and N. Florida. Arctic and alpine forms from Greenland west to Alaska, south to Hudson Bay; also in western mountains to Colorado and central California. Holarctic, occurring in Europe and Asia.
The eastern lowland form is very common in the North but rare in the South; eastern populations are more common than those in the West. Often considered pugnacious, the American Copper displays much seasonal and individual variation. The rare arctic and alpine forms are sometimes quite dingy.