Eminent Domain (in the Roman law, dominium eminens), the right of property possessed by a state, which is higher over all the goods and valuables within the state than that of any individual. Dominus and magister are both translated by the word "master;" but dominus means master by the right of property, while magister means master by the right of superiority. Hence dominium as a law term is quite accurately represented by the word property. The phrase eminent domain means, in practice, the right inherent in any sovereignty of taking possession of any valuable thing, be it real or personal, and using it for a public purpose. Where, in the theory of the law, all property is held by tenure from the sovereign, the exercise of this right may be regarded as only a resumption of that which it originally granted; and all property may be supposed to rest on a title to which the condition was annexed that it might be thus resumed by the original grantor. In this country, as in all other republics, the right of eminent domain rests on the paramount right of the public welfare.
Whatever be its ground, it is entirely certain that the right of eminent domain, or the right to take private property for public use, is distinctly asserted and frequently exercised, both by the national government and by that of the several states. One condition is always affixed to it, viz., that the public good requires that private property should thus be taken for public use; and this fact must be ascertained under legislative authority. Another condition is annexed to the exercise of this power by the constitution of the United States, and by that of many states - a condition which is universal in practice, and would doubtless be held to be always implied in law; it is that adequate compensation be made to those from whom the property is taken. The most common instances of the exercise of this power are in the case of lands taken for roads or canals; but it is, we conceive, quite certain that the principle itself is wholly unlimited, and that by virtue of it any property may be taken by the sovereign power from any owner, provided it is required for public use, and compensation is made to the owner from whom the property is taken.
The taking need not be by the sovereignty itself, but, under legislative authority, may be by corporations or individuals empowered to construct works of public utility; and in several of the United States it has been decided that the construction of mills and manufactories is so far a matter of public concern as to justify the appropriation of private property under the eminent domain to obtain the requisite water power.