The American cockroach (Periplaneta americana) is the largest common house cockroach, about 1.5 inches long and reddish-brown. It is often called a palmetto bug and favors warm, damp spots such as basements, sewers, and drains rather than kitchens.
The American cockroach is easy to place once you use one simple framework: the Size-and-Habitat check. This roach stands out by being big and reddish-brown, and by turning up in moist, lower-level areas rather than in the middle of a kitchen. Those two clues — how large it is and where you find it — separate it from the smaller, kitchen-dwelling German cockroach faster than any other detail. To see how the different species compare at a glance, it helps to review what cockroaches look like.
Scientifically it is Periplaneta americana. Despite the name, it is not the roach you most often meet indoors; the German cockroach is the main indoor pest. The American cockroach is instead the giant of the group, and its size alone usually gives it away.
American Cockroach Identification (Palmetto Bug)
The American cockroach is the largest of the common house cockroaches, reaching about 1.5 inches long. Its body is reddish-brown, and in many parts of the southern United States it goes by the nickname palmetto bug. Because of its size and color, it is hard to confuse with the small, light-brown German cockroach that measures only about 1/2 to 5/8 inch.
People often ask whether this roach flies. In practice, most house cockroaches do not truly fly. The American cockroach can glide or flutter briefly in warm conditions, but it does not sustain real flight — it mainly runs, and very fast. For a fuller look at that question, see do cockroaches fly.
American Cockroach — Key Field Marks
Feature
🪳 American Roach
🪳 German Roach
Species
Periplaneta americana.
Blattella germanica.
Size
Largest house roach, about 1.5 inches.
Small, about 1/2 to 5/8 inch.
Color
Reddish-brown; nicknamed palmetto bug.
Light brown with two dark stripes behind the head.
Flight
Can glide or flutter briefly in warmth; does not truly fly.
Does not fly.
The American cockroach is set apart by its large size and reddish-brown color. Sources: UC IPM; Penn State Extension.
Where American Roaches Live
The Size-and-Habitat check works because this species has clear preferences. American cockroaches favor warm, damp areas and are commonly found in basements, sewers, and drains. That is very different from the German cockroach, which is the species most often seen in kitchens and living spaces. The palmetto bug nickname itself points to its liking for moist, lower, and outdoor-adjacent spots.
Because cockroaches are nocturnal, seeing them out in the open during the day can suggest a larger population. If you are dealing with an active problem and want next steps, read our guide on how to get rid of cockroaches, and see the wider overview of all species on the cockroaches hub.
Where to Look First
Basements and other damp, dark lower levels
Sewers, floor drains, and plumbing access points
Warm, moist areas where water collects
These damp zones are the classic American cockroach habitat, unlike the kitchen focus of the German cockroach.
American vs Oriental Cockroach
Two large, moisture-loving roaches are often mixed up: the American and the Oriental cockroach. Applying the Size-and-Habitat check, plus color, sorts them out. The American cockroach (Periplaneta americana) is the largest house cockroach at about 1.5 inches and is reddish-brown. The Oriental cockroach (Blatta orientalis) is dark and glossy and favors damp, cool places such as drains. Both are drawn to moisture, so the dark body of the Oriental is the quickest color cue.
American vs Oriental Cockroach
Feature
🪳 American
🪳 Oriental
Species
Periplaneta americana.
Blatta orientalis.
Color
Reddish-brown; the palmetto bug.
Dark and glossy.
Where found
Basements, sewers, and drains.
Damp, cool places such as drains.
Color and body tone are the fastest split: reddish-brown American vs dark, glossy Oriental. Source: UC IPM.
Frequently Asked Questions
What is the American cockroach?
The American cockroach (Periplaneta americana) is the largest of the common house cockroaches, reaching about 1.5 inches long. It is reddish-brown and is often called a palmetto bug. Unlike the German cockroach, which is the main indoor pest, the American cockroach favors damp areas such as basements, sewers, and drains.
Why is the American cockroach called a palmetto bug?
Palmetto bug is a common nickname for the American cockroach (Periplaneta americana), especially in the southern United States. The name comes from the insect being found near palmetto plants and other moist outdoor and lower-level areas. It refers to the same reddish-brown, roughly 1.5-inch cockroach.
How big is an American cockroach?
The American cockroach is about 1.5 inches long, making it the largest of the common house cockroaches. Its size and reddish-brown color help separate it from the much smaller German cockroach, which is only about 1/2 to 5/8 inch and light brown with two dark stripes behind the head.
Where do American cockroaches live?
American cockroaches prefer warm, damp areas. Indoors and around buildings they are commonly found in basements, sewers, and drains, and other moist, dark spots. This is different from the German cockroach, which is the species most often found in kitchens and living areas of homes.
Can American cockroaches fly?
Not really. Most house cockroaches do not truly fly. The American cockroach can glide or flutter briefly in warm conditions, but it does not sustain flight the way a strong flying insect would. Like other roaches, it mainly runs very fast to escape.
What is the difference between an American and an Oriental cockroach?
The American cockroach (Periplaneta americana) is the largest house cockroach, about 1.5 inches, and reddish-brown. The Oriental cockroach (Blatta orientalis) is dark and glossy and favors damp, cool places such as drains. Both like moisture, but color, size, and the darker Oriental body help tell them apart.
Sources
UC IPM — Cockroaches (American cockroach, Periplaneta americana, is the largest house cockroach at about 1.5 inches, reddish-brown, the palmetto bug, favoring basements, sewers, and drains; Oriental cockroach, Blatta orientalis, is dark and favors damp, cool places; American cockroach can glide or flutter but does not truly fly).
Penn State Extension — German Cockroaches (German cockroach is the main indoor pest, about 1/2 to 5/8 inch, light brown with two dark stripes behind the head — used here for comparison).