Indiana was the fourth township formed in the county north of the Ohio and Allegheny rivers. Its organization was preceded by that of Pine and Deer in 1796, and Ohio in 1803, all of which were originally included in Pitt township. At the June sessions, 1805, on petition of a number of citizens of Deer, praying for the formation of a new township from its territory to be described as follows: " Beginning at the mouth of Pine creek, on Allegheny river, upon the line dividing Jones’ district from Cunningham’s district (which is also the division line between Deer and Pine townships), and extending along the line of Cunningham’s district due north to the seven-mile tree in the said line, thence due east through Cunningham’s district to Bull creek, thence down said creek to Allegheny river, thence down the Allegheny river to the place of beginning," the court appointed as commissioners James Semple, Samuel Scott and James Robinson. December 26, 1805, their report, in which the bounds above described were recommended, was confirmed by the court, and the name of Indiana conferred upon the new district. The township was triangular in shape. The political significance of "the line dividing Jones’ district from Cunningham’s district" has been obliterated by the formation of Hampton and Shaler, of which the former derived one-half and the latter one-third of its area from Indiana. Its area had previously been curtailed by the erection of East Deer, when the present eastern boundary was established; and in 1875, by the formation of O’Hara and Harmar, the township was deprived of its former extended frontage upon the river. It is thus seen that as originally formed Indiana received fully one-half of the previous territory of Deer, and included within its limits, in addition to its present area, the whole of three townships and portions of an equal number of others.

The earliest settlers were Jacob Huddle and Henry Strohm, brothers-inlaw and native Germans. They are supposed to have arrived in 1798, although their deeds for lands transferred from Benjamin Herr are dated August 21, 1805. The first birth occurred in the family of Henry Strohm, but the child, a boy named Peter, died before attaining his majority. These two families are still numerously represented. Peter Weaver, Jacob Bave and Daniel Sweeney were also early settlers.

William Marshall, Robert Black, John McKee, James Patterson, Samuel McClellan, James Quinett, Peter Neff, John Eward, George Snyder, Elijah Brooks, James Powell, David Stewart and Thomas McWilliams were residents prior to 1820.

A grist- and saw mill was built on Deer creek more than half a century since by Robert McCaslin. It has been torn away. Another gristmill was erected farther down the same stream, about forty years since, by Peter Wise. It is now owned and operated by Michael Yonker, who has added to it a sawmill. A grist- and saw-mill was built more recently by Henry Strohm. The population in 1860 was 2,505; in 1870, 2,808; in 1880, 1,189.

The Kittanning road passes through the township. Deer, Little Deer and Cummings creeks are the principal streams. Dorseyville is a small hamlet which took its name from a man named Dorsey. It is the only village in the township. It has a postoffiee, and some stores and mechanic-shops. Montooth postoffice was established in 1882. The township has three churches — Walter chapel (Methodist Episcopal) in the northern part, a United Brethren society near Dorseyville, and a German Lutheran church in the same vicinity.