The average flow of the Arnold River is approximately 5 cubic metres per second (180 cu ft/s) and its watershed covers 265 kilometres (164.66 mi).

Following the disclosure of its report, the American Congress decides to send its troops to seize the valley of the St. Lawrence River.

The considerable difficulties encountered by this expedition helped the English to rout the Americans before the walls of Quebec on the night of 30 to December 31, 1775.

Transferred to Montreal, previously occupied by Montgomery, in April 1776, General Arnold must evacuate the city and return to the United States in June in the face of growing hostility from the Canadians and the arrival of British reinforcements.

[4] The toponym "rivière Arnold" was made official on December 5, 1968, at the Commission de toponymie du Québec.