Although the subspecies of painted turtle intergrade (blend together) at range boundaries they are distinct within the hearts of their ranges.

The male eastern painted turtle (C. p. picta) is 13–17 cm (5–7 in) long, while the female is 14–17 cm (6–7 in).
The upper shell is olive green to black and may possess a pale stripe down the middle and red markings on the periphery.
The segments (scutes) of the top shell have pale leading edges and occur in straight rows across the back, unlike all other North American turtles, including the other three subspecies of painted turtle, which have alternating segments.
The bottom shell is plain yellow or lightly spotted.
Sometimes as few as one dark grey spot near the lower center of the shell.

The midland painted turtle (C. p. marginata) is 10–25 cm (4–10 in) long.
The centrally located midland is the hardest to distinguish from the other three subspecies.
Its bottom shell has a characteristic symmetrical dark shadow in the center which varies in size and prominence.

The southern painted turtle (C. p. dorsalis), the smallest subspecies, is 10–14 cm (4–6 in) long.
Its top stripe is a prominent red, and its bottom shell is tan and spotless or nearly so.

The largest subspecies is the western painted turtle (C. p. bellii), which grows up to 26.6 cm (10 in) long.
Its top shell has a mesh-like pattern of light lines, and the top stripe present in other subspecies is missing or faint.
Its bottom shell has a large colored splotch that spreads to the edges (further than the midland) and often has red hues.
Although the subspecies of painted turtle intergrade (blend together) at range boundaries they are distinct within the hearts of their ranges.
The male eastern painted turtle (C. p. picta) is 13–17 cm (5–7 in) long, while the female is 14–17 cm (6–7 in). The upper shell is olive green to black and may possess a pale stripe down the middle and red markings on the periphery. The segments (scutes) of the top shell have pale leading edges and occur in straight rows across the back, unlike all other North American turtles, including the other three subspecies of painted turtle, which have alternating segments. The bottom shell is plain yellow or lightly spotted. Sometimes as few as one dark grey spot near the lower center of the shell.
The midland painted turtle (C. p. marginata) is 10–25 cm (4–10 in) long. The centrally located midland is the hardest to distinguish from the other three subspecies. Its bottom shell has a characteristic symmetrical dark shadow in the center which varies in size and prominence.
The southern painted turtle (C. p. dorsalis), the smallest subspecies, is 10–14 cm (4–6 in) long. Its top stripe is a prominent red, and its bottom shell is tan and spotless or nearly so.
The largest subspecies is the western painted turtle (C. p. bellii), which grows up to 26.6 cm (10 in) long. Its top shell has a mesh-like pattern of light lines, and the top stripe present in other subspecies is missing or faint. Its bottom shell has a large colored splotch that spreads to the edges (further than the midland) and often has red hues.
Painted turtle