County adjacent to Indianapolis-Marion County on the east and part of the Indianapolis Metropolitan Statistical Area. The families of Andrew Evans, John Montgomery, and Montgomery Call settled along Blue River in what is now Hancock County around 1818. They had established farmsteads by the time the U.S. government surveyed the area in 1819. However, the county itself was not created until 1828 when it was set off from Madison County and named after John Hancock. There were about 400 people living on scattered farmsteads throughout the county at that time. Most were Methodists, with settlers organizing a class meeting in the area by 1820. Greenfield became the county seat in 1828, and has always been the largest town in Hancock County. The other early towns in the county were Fortville and New Palestine.

Much of the land in the new county was low and swampy. Farmsteads were scattered on the few hills and knolls above Blue River and Sugar Creek. Gradually the county was drained through the use of tiled ditches and made into rich farmland. Residents exported large quantities of wheat, corn, oats, hogs, cattle, and sheep, and many county residents earned extra income by feeding or boarding travelers along the NATIONAL ROAD. Greenfield especially benefited from the Dayton coach, a passenger coach that made weekly trips between Indianapolis and Dayton, Ohio. The construction of railroads through Hancock County in the 1850s and 1860s spurred agricultural production and strengthened the connection between Greenfield and Indianapolis. The Indiana Central Railroad, completed in 1851, provided regular passenger service from Greenfield to the capital. Shortly after its completion Greenfield was incorporated as a town, and, in 1876, it became a city with 2,023 residents. Access to Indianapolis and its stores and markets improved in 1900 with the completion of the interurban line to Greenfield. An interurban line that ran from Indianapolis to Anderson through Fortville was completed in 1901.

The demise of the railroad and interurbans in the first quarter of the 20th century halted the rapid late 19th century growth of Greenfield and Hancock County The county has remained predominately rural and agricultural. The growth of Indianapolis during and after World War II, however, spurred suburban development in the western part of the county, and its total population nearly tripled between 1940 and 1980. This rate slowed considerably after 1980, and the 1990 figure of 45,527 was an increase of less than 2,000 from ten years earlier. Agriculture is still the county's main economic interest, but farmland has been converted to residential subdivisions in some areas.

The 1990 population of Greenfield was 11,657. The city has maintained a population of around 10,000 for the past 20 years. Both Greenfield and Hancock County are perhaps best known as the birthplace of Indiana poet JAMES WHITCOMB RILEY.