It was founded in 1884 as the Brockville, Westport & Sault Ste Marie Railway.

In 1894 the company was placed into receivership, and in 1903 it was sold by the court to a New York–based syndicate (Holm-Gerken-Schmitt-King) for $160,000 and re-incorporated as the Brockville, Westport and Northwestern Railway.

In 1921, passenger service was maintained by a 20-passenger REO gasoline-powered railcar.

An application to abandon the line from Lyn Junction to Westport was filed with the Board of Transport Commissioners in June 1951 and was approved (order number #49236) in 1952.

Service ended on the line August 30, 1952, and was scrapped in late 1952 into the summer of 1953.