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, Spencer County, Indiana
Eureka was laid out in 1858. A post office was established at Eureka in 1872, and remained in operation until it was discontinued in 1921. Tradition has it the community was so named after a pioneer exclaimed "Eureka!" when he came upon the site.