The 1900s represented a century of radical transformation for Clermont County. It began as a collection of isolated, agrarian river towns and ended as one of the fastest-growing suburban counties in the United States.
The Early 1900s: The Era of "Traction" and Floods
At the turn of the century, Clermont was still deeply rural, but the "Traction Era" (electric interurban railways) began to break its isolation.
The Interurban Boom: From 1907 to 1926, the Cincinnati, Milford & Blanchester (CM&B) and other traction lines connected towns like Milford and Batavia directly to Cincinnati. This allowed farmers to ship produce more quickly and began the very first "commuter" culture.
The Great Flood of 1913: This was a defining disaster for the region. The Ohio River and the Little Miami surged to record heights. Milford lost its funeral parlor and livery stable, and the river towns of New Richmond and Neville were nearly wiped out. This event spurred the first serious discussions about regional flood control.
A Governor from Clermont: In 1905, John M. Pattison of Owensville became the first Clermont County resident elected Governor of Ohio.
Mid-Century: War and Infrastructure
The middle of the 1900s saw Clermont County transition from the "Horse and Buggy" age to the "Atomic Age."
World War II and Industrialization
Clermont citizens contributed heavily to the war effort, both on the front lines and at home. The proximity to Cincinnati’s machine tool industry meant many residents worked in factories producing aircraft engines and munitions.
Post-War Housing: Following 1945, the "GI Bill" sparked a housing boom. The western edge of the county (Union and Miami Townships) began to see the first suburban subdivisions as families fled the crowded city center of Cincinnati.
The Coming of the Interstate
The most significant development for the county's modern history was the construction of Interstate 275 (the Circle Freeway) and State Route 32 (the Appalachian Highway) in the late 1960s and 70s.
The Shift: These roads shifted the county's economic heart away from the Ohio River towns and toward the "uplands" like Eastgate and Union Township. This made Clermont a prime location for retail and regional distribution.
Late 1900s: The Creation of East Fork Lake
One of the largest physical changes to the county’s map occurred in the 1970s.
The Project: Authorized for flood control, the William H. Harsha Lake (East Fork Lake) was created by damming the East Fork of the Little Miami River.
The Sacrifice: To create the lake, the Village of Elk Lick and the community of Twin Bridges as well as surrounding farms were evacuated and submerged. Historic homes, like the Elk Lick House (the final home of Senator Thomas Morris), had to be physically moved to save them from the rising waters.
The Progress: Today, the lake provides water to the county and serves as a major recreational hub, hosting national rowing competitions and thousands of campers.
Notable People of the 1900s
Beyond Governor Pattison, the 1900s saw several Clermont residents rise to prominence:
| Name | Role / Achievement | Significance |
| Hugh L. Nichols | Chief Justice | A Batavia resident who became the first Chief Justice of the Ohio Supreme Court (1914). |
| Jean Schmidt | Politician | A Miami Township resident who became the first woman from Southern Ohio elected to Congress. |
| John J. Voll | Ace Pilot | A Goshen native and the top-scoring Army Air Force ace in the Mediterranean Theater during WWII. |
| Josephine Johnson | Author | Lived in the county; won the Pulitzer Prize in 1935 for her novel Now in November. |
| Decade | Focus of Progress |
| 1900–1920 | Electric Traction Lines and recovery from the 1913 Flood. |
| 1920–1940 | Paving of the first major highways and rural electrification. |
| 1940–1960 | Suburbanization begins; birth of the modern middle class. |
| 1960–1980 | I-275 construction and the completion of the East Fork Dam. |
| 1980–1999 | Retail explosion (Eastgate Mall) and the county population doubling. |