The northeast boundary of the city is the Utah County line, following the height of land.

7,828-foot (2,386 m) Packard Peak is to the north, while 8,048-foot (2,453 m) Godiva Mountain and 7,917-foot (2,413 m) Eureka Ridge are to the south.

According to the United States Census Bureau, Eureka has a total area of 1.5 square miles (3.9 km2), all land.

Eureka was originally known as Ruby Hollow before it developed into a bustling mining town.

Eureka's role as the central financial point for the district ensured its survival.

It housed business establishments, including the second-ever JCPenney store (then called the Golden Rule Store), financial institutions, local and county governmental buildings including Eureka City Hall (1899) and a Juab County Courthouse (1892), various churches, and the meeting places for numerous labor, social, and fraternal organizations.

Mining entrepreneurs such as John Q. Packard [Wikidata], John Beck (who personally funded the construction of the Eureka LDS Church Meetinghouse in 1902), Jesse Knight, and Walter Fitch Sr. were important figures in Eureka and Tintic history.