One of North America's biggest insect collections is on the UC Berkeley campus. The Essig Museum of Entomology says it houses an active research collection of over 5 million terrestrial arthropods.
From teaching drawers to a survey
The collection began over a hundred years ago as a teaching collection, the museum says. Wikipedia dates its origins to the 1880s. Entomologist Edward Oliver Essig joined the faculty in 1914 and began expanding it. The research collection was formalized in 1939 as part of the California Insect Survey. It was named the Essig Museum of Entomology in 1972.
Wikipedia says it may hold the world's largest collection of California insects. The museum's focus has broadened to the eastern Pacific Rim, including Mexico, Central America and the central Pacific islands.
Can you visit?
Not on a regular basis. Wikipedia says the museum opens to the public twice a year, on Cal Day and Darwin Day. The museum's site says it also held a Saturday open house during Homecoming on Oct. 10, 2026.
You can still get involved from home. The museum has asked people to report swarms of California oak moths or their caterpillars. It also posts tips for identifying insects and spiders. When you ask for help, it suggests noting the location, habitat and behavior.