## Facts

- Cyrus Alger owned upland property abutting Boston Harbor and claimed rights in adjoining tidal flats under the Colony Ordinance of 1641–47.
- The Colony Ordinance granted upland owners a fee interest in nearby flats (above low-water mark and within a set distance) with power to build wharves, but made the grant subject to public navigation rights and to legislative “restraints and limitations” protecting public and private rights.
- Massachusetts enacted statutes to preserve Boston Harbor by establishing fixed “commissioners’ lines” beyond which no wharf could be extended or maintained and declaring structures beyond the line to be public nuisances.
- Alger built and maintained a wharf extending beyond the statutory harbor line, though it lay within the area the ordinance would otherwise have allowed and did not cause proven, case-specific obstruction to navigation.
- The Commonwealth indicted Alger for violating the harbor-line statutes by erecting and maintaining a wharf beyond the line; the matter was reported for determination of the statutes’ validity.

## Issues

1. Whether the legislature may, under the police power, prospectively limit wharfing and construction in navigable waters by fixed harbor lines and treat violations as public nuisances.
2. Whether such limits constitute a taking of private property for public use requiring compensation under the Massachusetts Declaration of Rights.
3. Whether the harbor-line statutes impermissibly impair rights purportedly granted by the Colony Ordinance in violation of the Contracts Clause.

## Decision

- The court upheld the harbor-line statutes as a valid exercise of legislative authority to protect public rights in navigation and the harbor.
- The court held that declaring wharves beyond the established line to be public nuisances was permissible even without proof that a particular wharf actually obstructed navigation.
- The court rejected the claim that the statutes effected a compensable taking, characterizing them as regulatory restraints rather than an appropriation of property for public use.
- The court rejected the Contracts Clause argument, concluding the Colony Ordinance did not create an unalterable contract and, in any event, expressly contemplated future legislative limitations.
- The indictment was sustained based on Alger’s construction and maintenance beyond the statutory line.

## Legal Principles

- Private property rights, including rights in tidal flats, may be subject to reasonable legislative regulation to protect public and private rights, especially in navigable waters.
- A general law that restrains harmful or potentially harmful uses of property under the police power is not a “taking” requiring compensation when it does not appropriate the property to public use.
- The legislature may define and prevent public nuisances through prospective, categorical rules (such as harbor lines), without case-by-case proof of actual injury in each prosecution.
- A general rule of property established by legislation, and expressly qualified by a reservation of future regulatory authority, is not insulated from later regulation by the Contracts Clause.
- Harbor-line restrictions operate prospectively; they bar new extensions beyond the line and do not retroactively invalidate structures lawfully built before the restriction.

## Conclusion

The court sustained enforcement of Boston’s harbor-line regime, holding that statutory limits on wharf construction beyond fixed lines are a valid police-power measure to protect navigation and harbor integrity, not a compensable taking and not an unconstitutional impairment of any contractual grant.


Commonwealth v. Alger, 61 Mass. 53 (1851)