This township was formed from Fawn in 1863. "Mellen" was suggested as the name in a petition presented at the June sessions, 1862. C. Snively, Caleb Lee and Jacob Alter constituted the commission by which the proposed territory was surveyed. Popular sentiment was strongly in favor of the measure, and when the question was submitted at the polls, February 28, 1863, there were but two dissenting votes in a total of one hundred and fifty-two. This action by the people was formally confirmed by decree of court, February 7, 1863. A noticeable occurrence in this connection was the payment of two hundred and fifty dollars by the tax-collectors of the new subdivision to the court for disbursement to the supervisors of Fawn, in lieu of an equal amount expended upon the opening of a road in the former just prior to the division.

James Kerns, whose mother was one of the Jack family, was an early settler in Harrison township. He resided on the river bank about three miles above Tarentum. Several of his descendants are residents here. John Miller was also an early resident, about one mile from Freeport, near the Butler county line, on what was then called the Kittanning and Pittsburgh road. His son Nathaniel was a lifelong resident of the township. Asa Rowley settled early on the same road, about four miles from Tarentum, where he remained till his death. Philip Burkner settled on Little Bull creek, about a mile from the Allegheny river, and there he died. His granddaughter, Mrs. Huey, resides on the place where he settled. William Owns, a Portuguese, was a squatter on the bottom-lands near where the Natrona Chemical works now are. He was on quite intimate terms with the Indians, and was an expert hunter. He died at that place many years since.

A man named Derry was also a squatter at the same place, and a neighbor of Owns, with whom he was not on good terms. Just prior to the commencement of the present century the Indians surprised and murdered the family and burned their house. A son, named Jacob Derry, escaped by hiding in a hollow which the river had excavated under a beech stump. A grandson of Jacob now resides near Oil City. It was believed that this murder was instigated by Owns.

In 1807 John and William Kennedy located in what is now Tarentum. In 1810 they removed to what were known as the "Bottoms," where they remained till 1817, when they removed to a place across the river. Many of their descendants are residents of this vicinity. John Kennedy, a son of William, and the father of John and James Kennedy, bankers in Tarentum, is still living at the age of eighty-four. The descendants of the original John have removed from this region.

Jacob Krom came about 1807, and settled near John Miller, a mile from Freeport, on a place now owned by Henry Boyd. He and several of his children died at the place where he settled. About a year since his son, Isaac Krom, died, at the age of eighty-seven, in Tarentum. Several of the descendants reside in this vicinity. Near to Mr. Krom, and at about the same time, Mr. Washington Bale settled. His daughter, Mrs. Altor, still resides on the old place. Andrew McGinnis settled on the bottom about 1810, and remained some ten years.

After the first decade of this century the region along the Allegheny river was rapidly settled. During twenty or thirty years, or till about 1835, the country back from the river was a wilderness.

Natrona. — About 1853 the manufacture of salt was commenced at this place. At that time there was no village here. Several wells were sunk from which brine was obtained, and salt was made to some extent. This of itself had, however, no great importance. Works were at once erected for the manufacture of various chemical substances, and these works have since been steadily increased to the present day. The company which is engaged in these manufactures is chartered as the Pennsylvania Salt company, but the manufacture of salt is only a small item.

One of the first articles made here was caustic soda, from which concentrated lye was prepared. To this were added bromine, chloroform, various acids, pure soda and its salts, aluminum and various other chemical substances. The products of these works are sold in all parts of the United States and Canada. The cryolite from which soda and aluminum are largely produced here is brought from Greenland, the only known place where deposits of it exist. The pyrites from which sulphuric acid is produced are brought from Spain. Copper as well as silver and gold is extracted from the materials used in the manufacture of chemicals here.

The village of Natrona owes its existence to the establishment of these works. About six hundred operatives are employed by the company, and the village has a population of about fifteen hundred. There are five church organizations in the place, viz. : Methodist, Catholic, German Lutheran, Presbyterian and English Lutheran. All except the last have tasteful and convenient houses of worship.

The population of the township in 1870 was 1,870; in 1880, 2,352. There are small hamlets at Sligo and Karns stations.