It rises in northern Strafford County and runs southeastward, through the town of Farmington and the cities of Rochester and Dover, where it provides hydroelectric power.

In 1642, Richard Waldron was granted water privileges at Cochecho Falls, moving there from Dover Point to build a sawmill and gristmill.

But as historian Caroline Harwood Garland writes, "By an error of the engrossing clerk in the act of incorporation, the old Indian word, Cochecho, became Cocheco.

"[2] As historian Alonzo Hall Quint laments: "The chief fault of the present Company is their barbarous spelling of 'Cocheco' instead of 'Cochecho,' for which no possible excuse exists.

"[3] In an 1851 essay written for the Dover Enquirer, Quint records the history of the Cochecho River's name: It has been ill-treated in a most serious manner.

"[4] In 1909, Pacific Mills of Lawrence, Massachusetts bought the Cocheco Manufacturing Company and set about making changes, one of which was to end the disparity between the river's historic spelling and its brand.

All that remains of the mill are its repurposed factory buildings, listed on the National Register of Historic Places, and its brand name on the river.