[1] The region stretching from the northern side of Harmar Township, Pennsylvania to the Kiskiminetas towns is often referred to by the locals as the Alle-Kiski Valley after the rivers.

The Kittanning Path, a major trail in the region used by Native Americans and early European settlers, crossed the river at a ford near present-day Leechburg.

According to regional historians in the area, the name has historically had several other possible meanings, including: "river of the big fish" and "plenty of walnuts."

Robert Walker Smith in his "History of Armstrong County, Pennsylvania" (Chicago: Waterman, Watkins & Co., 1883) reported that John Heckewelder (a Moravian writer, explorer, and historian who wrote about the Lenape and other tribes in Western Pennsylvania in the 18th century) claimed that the name is "corrupted from Gieschgumanito, signifying, make daylight.

Smith also described another possible meaning from another source: "It is said in McCullough's Narrative, that the Indians called this river Kee-ak-ksheman-nit-toos, signifying 'cut spirit'."