The case arose from a controversy that came to be known as the "Lumbermen's Feud".
Peter McLaren owned a lumber mill and had added timber slides on the Mississippi river and its northern tributaries that flowed through land that he owned in Lanark County, Ontario, in order to provide for transporting his own logs.
Boyd Caldwell owned a rival mill, and was attempting to drive 18,000 logs through those slides.
McLaren sued Caldwell's firm, B. Caldwell & Son, to restrain them from passing or floating timber and saw logs through his slides.

Caldwell claimed that McLaren was unable to prevent the use of the river for the passage of his logs because of the statutes in force in Ontario.
McLaren, however, asserted that he had the right to do so under the common law.

In support of Caldwell, Ontario Premier Oliver Mowat arranged the passage of the Rivers and Streams Act, 1881 which required the unobstructed passage of logs, timber, rafts, etc.
down all waterways in the province, whether improved or not, subject to the payment of any reasonable tolls.
This Act was disallowed by the federal government under Sir John A. Macdonald on the grounds that it infringed upon private property rights.
This conflict added fuel to the ongoing quarrel between the federal and provincial governments; the bill was re-enacted and disallowed again in 1882 and 1883.

In an 1882 debate in the Legislative Assembly of Ontario, Mowat maintained that the Rivers and Streams Bill fell wholly within provincial jurisdiction, and asserted that federal disallowance could only take place:
when the Act is altogether illegal or unconstitutional,
when illegal or unconstitutional in part,
in cases of concurrent jurisdiction as clashing with the legislation of the General Parliament
when it affects the interests of the Dominion Parliament.
The case arose from a controversy that came to be known as the "Lumbermen's Feud". Peter McLaren owned a lumber mill and had added timber slides on the Mississippi river and its northern tributaries that flowed through land that he owned in Lanark County, Ontario, in order to provide for transporting his own logs. Boyd Caldwell owned a rival mill, and was attempting to drive 18,000 logs through those slides. McLaren sued Caldwell's firm, B. Caldwell & Son, to restrain them from passing or floating timber and saw logs through his slides.
Caldwell claimed that McLaren was unable to prevent the use of the river for the passage of his logs because of the statutes in force in Ontario. McLaren, however, asserted that he had the right to do so under the common law.
In support of Caldwell, Ontario Premier Oliver Mowat arranged the passage of the Rivers and Streams Act, 1881 which required the unobstructed passage of logs, timber, rafts, etc. down all waterways in the province, whether improved or not, subject to the payment of any reasonable tolls. This Act was disallowed by the federal government under Sir John A. Macdonald on the grounds that it infringed upon private property rights. This conflict added fuel to the ongoing quarrel between the federal and provincial governments; the bill was re-enacted and disallowed again in 1882 and 1883.
In an 1882 debate in the Legislative Assembly of Ontario, Mowat maintained that the Rivers and Streams Bill fell wholly within provincial jurisdiction, and asserted that federal disallowance could only take place:
when the Act is altogether illegal or unconstitutional,
when illegal or unconstitutional in part,
in cases of concurrent jurisdiction as clashing with the legislation of the General Parliament
when it affects the interests of the Dominion Parliament.
McLaren v Caldwell