Eureka, California
"Eureka" received its name from a Greek word meaning "I have found it!" This exuberant statement of successful (or hopeful) gold rush miners is also the official motto of the State of California. Eureka is the only U.S. location to use the same seal as the state for its seal.
Eureka, Illinois
Eureka was originally laid out as "Walnut Grove" in 1855. The name was changed to "Eureka" because of a naming conflict with another Walnut Grove. Sources differ on who proposed the name Eureka. The city is named from the Greek expression Eureka, meaning "I have found it".