| Official Name: | Eureka |
| Pushpin Map: | Indiana#USA |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Indiana |
| Subdivision Type2: | County |
| Subdivision Name2: | Spencer |
| Subdivision Type3: | Township |
| Subdivision Name3: | Luce |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Coordinates: | 37.8806°N -87.215°W |
| Elevation Footnotes: | [1] |
| Elevation Ft: | 390 |
| Postal Code Type: | ZIP code |
| Postal Code: | 47635 |
| Area Code: | 812 |
| Blank Name: | FIPS code |
| Blank Info: | 18-21592[2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 434247 |
Eureka is an unincorporated community in Luce Township, Spencer County, in the U.S. state of Indiana.
Eureka was laid out in 1858.[3] A post office was established at Eureka in 1872, and remained in operation until it was discontinued in 1921.[4] Tradition has it the community was so named after a pioneer exclaimed "Eureka!" when he came upon the site.[5]
Eureka is located at 37.8806°N -87.215°W.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Eureka has a humid subtropical climate, abbreviated "Cfa" on climate maps.[6]