Decatur Township is located in the southwestern part of Marion County and named for Stephen Decatur, a hero of the War of 1812.
In 1819, three years before the township was organized, settlers had cleared dense hardwood forests and established farms along theor near the district’s many springs. Many early residents were Quakers who moved to the area from the Carolinas. In 1827 they established the first Sanders Creek Meeting of Friends.
Small settlements sprang up along key roads or near rail lines. Northport was platted in 1839, though the name was changed to Fremont in 1856 and later to Valley Mills. The town prospered as a stop on the Indianapolis and Vincennes Railroad, constructed in 1867. Farther south, Newton (later changed to) was laid out by Christopher Furnas in 1851.
During the Civil War, the Mooresville Road was built through the community. Another settlement. Spring Valley, platted in 1848, survived only a brief time, though its rivals. West Newton and Valley Mills, boasted shops, schools, churches, and small businesses in the 1880s.was laid out and named by Don Carlos Morgan in 1890. Located along the railroad and, later, a state highway, Camby served travelers and local farmers. first came to Camby and other township communities in the early 1900s, though the lines were abandoned in the 1920s.
One impetus for growth was the opening of the Indianapolis Municipal Airport in 1931 on the Decatur Township-Wayne Township line. Improved motor routes also spurred township development. A state highway S.R. 67 (Kentucky Avenue), constructed in the 1930s, was widened in the 1950s to accommodate increased traffic. In the 1960s and 1970s, I-465 and I-70 were built across the northern sector of the township. Intensive residential development in some of the township’s northern areas began after World War II when Indianapolis factories, such as Detroit Diesel Allison Division of General Motors, expanded the workforce.
Though several new subdivisions were built, the district did not experience the dramatic growth of other Marion County townships, in part because of a lack of key thoroughfares to Indianapolis and limited access to the interstate system. Throughout the 19th century, the township counted less than 1,600 residents. By 1940 that number had increased to nearly 4,000. From 1950 to 1980 the population grew from about 6,000 to over 19,000.
In the early 1990s, the largest employers in the township included Indianapolis Power and Light Company,, and the Metropolitan School District of Decatur Township, which was not part of the city-county consolidation in 1970. District schools include six elementary schools, one middle school, and two senior high schools.
Notably, in 2008 theopened a new 1.2-million-square-foot midfield passenger terminal. The expansion allowed Federal Express to increase its operations making its Indianapolis hub the second largest in the world. In 2019 India-based technology service and consulting company opened its U.S. Training Center at the site of the old airport terminal bringing over 3,000 jobs to the area.
Though much of the district is still farmland, there has been new residential and commercial development, including the Ameriplex Industrial Park located on 1500 acres with 15 million square feet of warehousing, manufacturing, office, retail, and restaurant space. The Ronald Reagan Parkway, completed in stages during the first two decades of the 21st century, connects the southern terminus of Ameriplex Park to I-70 near the airport, thereby opening the township to future development.