It is not the city you would expect to have one of the most serious bug problems in the country. And yet, for five years straight, the same winner keeps showing up.
Los Angeles tends to dominate travel conversations for its sunshine, its celebrity sightings, and its theme parks.
But a new report from pest control company Orkin has handed it a far less glamorous title: the worst city in the United States for mosquito activity. That ranking has been held every single year since 2021.
Why Los Angeles Keeps Topping the List
The report, which measured the volume of new residential pest treatments between March 2025 and March 2026, places L.A. firmly ahead of every other major American city.
Chicago came in second, followed by New York City in third and Detroit in fourth. Atlanta, which previously held the No. 1 spot for six consecutive years, dropped to fifth place.
Orkin entomologist Shannon Sked pointed to shifting climate patterns as a key driver. Mosquito activity has been spreading beyond its traditional strongholds, with the yellow fever mosquito in particular expanding its range and creating new hotspots across the country.
The Surprise Climbers on This Year’s List
Milwaukee, Wisconsin landed at No. 23 overall but recorded one of the sharpest year-over-year jumps, climbing 15 spots compared to last year’s report. That kind of movement suggests that cities not historically associated with mosquito problems are starting to feel real pressure.
Florida, somewhat surprisingly, did not place any city in the top ten for mosquitoes. Miami, however, leads the country in a different pest category entirely, ranking as the worst city in the U.S. for termites.
What Travelers Should Know Before Heading Outdoors
Mosquitoes are more than a nuisance. They are capable of transmitting serious illnesses, including West Nile virus, dengue, malaria, yellow fever, and the Zika virus.
The Centers for Disease Control and Prevention recommends using insect repellents that contain DEET, oil of lemon eucalyptus, or para-menthane-diol (PMD).
Wearing loose-fitting, long-sleeved shirts and pants adds another layer of protection when spending extended time outdoors.
For travelers heading beyond U.S. borders, the risks go further. The CDC has flagged the chikungunya virus as currently active in several destinations, including the Seychelles, Mauritius, French Guiana, Bolivia, Suriname, and Mayotte.
Checking health advisories before travel, particularly for tropical and subtropical regions, is always worth the extra step.
Los Angeles is still an extraordinary destination. Universal Studios Hollywood, Disneyland, world-class dining, and reliably warm weather make it one of the most visited cities in the country. Just pack the bug spray.