Cicadas are large insects known for the males’ extraordinarily loud, distinct songs, which are produced by vibrating membranes on their abdomens. The distribution of these insects across the United States depends entirely on the type of cicada present. They spend most of their lives underground as nymphs, feeding on the sap of tree roots, before emerging briefly as adults to mate. This reliance on the subterranean environment and long life cycles means their geographical presence is specific. Understanding the two main types, annual and periodical, is necessary to determine which states host these singing insects.
Annual and Periodical Types
Cicadas in the U.S. are categorized into two groups based on their emergence schedules: annual and periodical. Annual cicadas, often called “Dog-day” cicadas, belong to the genus Neotibicen and appear every summer. While they are present yearly, their individual life cycles last between two and five years underground before they mature. Because generations overlap, some individuals complete their cycle and emerge as adults each year, making their presence an annual event.
Periodical cicadas, belonging to the genus Magicicada, are unique to eastern North America and have a much longer, synchronized life cycle. These insects remain beneath the soil for either a precise 13-year or 17-year period, emerging en masse only when that specific time interval is complete. This highly synchronized, massive emergence is what makes them so noticeable in the states where they occur. The 17-year species are found in the northern regions, while the 13-year species are more common in southern and midwestern states.
Widespread Presence of Annual Cicadas
Annual cicadas are far more widespread than their periodical relatives. These large, green and black insects can be found in almost every continental state. They emerge during the late summer months, from July through September, after the major periodical broods have already come and gone. Every state in the continental U.S. hosts at least four species of these annual cicadas, with some states like Arizona and California having dozens of species.
Specific States for Periodical Brood Emergence
The geographical range of periodical cicadas is restricted to the eastern and midwestern portions of the nation. These synchronized populations are organized into distinct groups known as “broods,” which are designated by Roman numerals. The 17-year broods, such as Brood X (last emerged in 2021), have a wide distribution that includes:
- Delaware
- Georgia
- Illinois
- Indiana
- Kentucky
- Maryland
- Michigan
- New Jersey
- New York
- Ohio
- Pennsylvania
- Tennessee
- Virginia
- West Virginia
This northern group covers a large number of states, often in smaller, fragmented patches.
The 13-year broods are concentrated in the Southern and Mississippi Valley states. Brood XIX, often called the Great Southern Brood, is the largest of the 13-year groups and covers a wide swath of states. Its distribution includes:
- Alabama
- Arkansas
- Georgia
- Illinois
- Indiana
- Iowa
- Kentucky
- Louisiana
- Mississippi
- Missouri
- North Carolina
- Oklahoma
- South Carolina
- Tennessee
- Virginia
The presence of a specific brood is limited to certain counties within these states, meaning not every resident will experience the emergence.
Ecological Factors Shaping Their Range
The specific distribution of periodical cicadas is governed by strict ecological requirements that limit them to the eastern half of the country. They require established deciduous forests, as the nymphs spend their subterranean lives feeding exclusively on the xylem fluid from tree roots. This necessity means that areas with significant land use changes, such as urbanization, often lose their cicada populations.
Emergence is triggered by an environmental cue: the soil temperature at a depth of about eight inches must reach approximately 64 degrees Fahrenheit. This temperature requirement restricts their northern range, as colder climates prevent the nymphs from completing their development or emerging successfully.