Public trust doctrine

The public trust doctrine is the principle that the sovereign holds in trust for public use some resources such as shoreline between the high and low tide lines, regardless of private property ownership.

The ancient laws of the Roman Emperor Justinian held that the sea, the shores of the sea, the air and running water was common to everyone. The seashore, later defined as waters affected by the ebb and flow of the tides could not be appropriated for private use and was open to all. This principle became the law in England as well. In the Magna Carta in England centuries later public rights were further strengthened at the insistence of the nobles that fishing weirs which obstructed free navigation be removed from rivers.

These rights were further strengthened by later laws in England and subsequently became part of the common law of the United States as recognized in Illinois Central Railroad v. Illinois, 146 U.S. 387 (1892). In that case the Illinois Legislature had granted an enormous portion of the Chicago harbor to the Illinois Central Railroad. A subsequent legislature sought to revoke the grant, claiming that original grant should not have been permitted in the first place. The court held that common law public trust doctrine prevented the government from alienating the public right to the lands under navigable waters (except in the case of very small portions of land which would have no effect on free access or navigation).

The public trust applies to both waters influenced by the tides and waters that are navigable in fact. The public trust also applies to the natural resources (mineral or animal) contained in the soil and water over those public trust lands.

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