[5] The area of modern-day Delhi Township was first settled by European Americans in 1789 with the founding of the village of South Bend.

Delhi was later split from the southern portions of Green Township in 1816 as a result of a petition from residents.

Upon incorporation, the township's name was originally spelled as "Delhigh", although the name morphed into "Delhi" sometime in the nineteenth century for unknown reasons.

[7] Now known as the Delhi Springhouse, the structure stands on land near the stone house Colonel Cornelius Ryker Sedam built in 1796.

Unincorporated communities in the township include Delhi Hills, Delshire, and Mount Saint Joseph.

[2] The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.

[14] Following an 1850s grape blight which destroyed most of the township's vineyards, many growers turned to vegetable farming.

On the heels of a successful transition to vegetable farming, growers began to construct greenhouses in order to extend the growing season.

The peak of local hothouse agriculture was reached during the late pre-WWII years, when as many as 55 family-run greenhouses operated in the township.

Notably, Delhi Township-based greenhouses produced a significant percentage of carnations supplied throughout the United States by this time.

The importance of greenhouses in Delhi Township was even reflected in the equipment of the Delhi Township Fire Department; as late as 1986, small-diameter fire attack lines were equipped with iron pipe couplings (rather than otherwise ubiquitous National Standard threads) in order to be compatible with the fittings in use on most greenhouse irrigation standpipes of the time.

This arrangement permitted firefighters to connect their hoses to the source of water closest to an interior greenhouse fire, eliminating the need to drag (potentially) hundreds of feet of heavy, charged hose connected at the fire apparatus's pump panel outside.

The requirement to carry a large variety of thread adapters (in order to be compatible with nearby, mutual aid departments), along with the rapid, penultimate decline of hothouse agriculture in Delhi Township led to the complete standardization to National Standard-threaded couplings within the department by the late 1980s.

Today, only a few family-run greenhouses remain—the combined results of a decline in business due to foreign flower imports, as well as the lucrative conversion of greenhouse properties to land made available for residential and commercial development in the post-World War II suburbanization boom.

[20] The Public Library of Cincinnati and Hamilton County operates the Delhi Township Branch.

The township first received a library in 1949 when a collection of books opened in Delhi Public School.