Opinion of the Court. should be common highways, forever free, without any tax or duty, Mr. Justice Field, for the court, on page 548, said: "The exaction of tolls for passage through the locks is as compensation for the use of artificial facilities constructed, not as an impost upon the navigation of the stream. The provision of the clause that the navigable streams should be highways without any tax, impost or duty, has reference to their navigation in their natural state. It did not contemplate that such navigation might not be improved by artificial means, by the removal of obstructions, or by the making of dams for deepening the waters, or by turning into the rivers waters from other streams to increase their depth. For outlays caused by such works the State may exact reasonable tolls. They are like charges for the use of wharves and docks constructed to facilitate the landing of persons and freight, and the taking them on board, or for the repair of vessels. The State is interested in the domestic as well as in the interstate and foreign commerce conducted on the Illinois River, and to increase its facilities, and thus augment its growth, it has full power. It is only when, in the judgment of Congress, its action is deemed to encroach upon the navigation of the river as a means of interstate and foreign commerce, that that body may interfere and control or supersede it. If, in the opinion of the State, greater benefit would result to her commerce by the improvements made, than by leaving the river in its natural state, and on that point the State must necessarily determine for itself, it may authorize them, although increased inconvenience and expense may thereby result to the business of individuals. How the highways of a State, whether on land or by water, shall be best improved for the public good is a matter for state determination, subject always to the right of Congress to interpose in the cases mentioned.” - And in the last of these cases, where the Manistee River was improved under authority of the legislature of the State of Michigan, and tolls exacted for the use of the improved water way, we find this in the opinion, on page 295: "The internal commerce of the State that is, the commerce which is wholly confined within its limits is as much under its con Opinion of the Court. trol as foreign or interstate commerce is under the control of the general government; and, to encourage the growth of this commerce and render it safe, the States may provide for the removal of obstructions from their rivers and harbors, and deepen their channels, and improve them in other ways, if, as is said in County of Mobile v. Kimball, the free navigation of those waters, as permitted under the laws of the United States, is not impaired, or any system for the improvement of their navigation provided by the general government is not defeated. 102 U. S. 691, 699. And to meet the cost of such improvements, the States may levy a general tax or lay a toll upon all who use the rivers and harbors as improved. The improvements are, in that respect, like wharves and docks constructed to facilitate commerce in loading and unloading vessels. Huse v. Glover, 119 U. S. 543, 548. Regulations of tolls or charges in such cases are mere matters of administration, under the entire control of the State." Kindred to these are the cases of Gilman v. Philadelphia, 3 Wall. 713; Transportation Company v. Chicago, 99 U. S. 635; Escanaba Company v. Chicago, 107 U. S. 678; Cardwell V. American Bridge Co., 113 U. S. 205; and Willamette Bridge Company v. Hatch, 125 U. S. 1, 12, in which the power of a State, in the absence of Congressional action, to obstruct navigation by the construction of bridges across navigable streams, was sustained. And, also, the cases of Packet Co. v. Keokuk, 95 U. S. 80, and Transportation Co. v. Parkersburg, 107 U. S. 691, in which the power of a State, under like circumstances to improve the border of streams by wharves and exact wharfage therefor, was affirmed. While in a matter of this kind it is needless to look for authorities beyond the decisions of this court, yet the cases of Kellogg v. Union Company, 12 Connecticut, 6, and Thames Bank v. Lovell, 18 Connecticut, 500, may be referred to as containing very satisfactory discussions of this question. We quote from the opinion in the latter case, page 511: "These acts, improving rivers, constructing roads, etc., will never be complained of, as interfering with the rights and powers of Congress. The tolls alone are the subject of com Opinion of the Court. plaint. But these are only the fair equivalent for privileges which the State had a right to create, and without which these privileges could never have existed. Commerce, therefore, has not been crippled by the tolls, as the defendant claims, but has been extended by them. The legislature of the State creating this corporation, with its duties and its privileges, has come in aid of the powers of Congress. "It seems to be admitted, that States may construct canals, turnpikes, bridges, etc., and impose tolls upon passengers and freight, as a remuneration for the improvements; and that this may be done, without interfering with the power of Congress to regulate commerce among the States, or its power to establish post-offices and post-roads. We have not been able to discover a sound distinction between these cases and the one we are considering. Congress has the same power to regulate commerce upon the land as upon the water. A river, to be sure, is a natural channel; but if it is not a navigable one, it can no more be used for the purposes of commerce than the land; and, therefore, to convert it from the mere natural channel into a public highway, for commercial purposes, and to levy a toll to reimburse the expense, no more conflicts with the powers of Congress over the commerce of the country than the construction of a canal or a turnpike for the same purposes, with the same tolls. And this, we think, is equally true of rivers, which are only navigable to a partial and limited extent, and by artificial and expensive means are rendered navigable to a greater extent, with a reasonable toll levied upon those only who receive the benefit of the extended navigation. The principle is the same in both the cases stated." But in this case there was not only the full authority of the State of Pennsylvania, but also, so far as respects this particular lock and dam, they were constructed at the instance and implied invitation of Congress. The act of March 3, 1881, making an appropriation for the improvement of the river, in terms provided that no such improvement should be made until the Navigation Company had in good faith started upon the building of this lock and dam. This lock and dam connected the lower improvements already made by the Naviga Opinion of the Court. tion Company with the upper improvements proposed to be made by Congress, and the appropriation by the latter was conditioned on the company's undertaking their construction. This is something more than the mere recognition of an existing fact; it is an invitation to the company to do the work; and when in pursuance of that invitation, and under authority given by the State of Pennsylvania, the company has constructed the lock and dam, it does not lie in the power of the State or the United States to say that such lock and dam are an obstruction and wrongfully there, or that the right to compensation for the use of this improvement by the public does not belong to its owner, the Navigation Company. Upon what does the right of Congress to interfere in the matter rest? Simply upon the power to regulate commerce. This is one of the great powers of the national government, one whose existence and far-reaching extent have been affirmed again and again by this court in its leading opinions, and the power of Congress over such natural highways as navigable streams is confessedly supreme. See among the various cases in which this supremacy has been affirmed: Gilman v. Philadelphia, 3 Wall. 713, 725; County of Mobile v. Kimball, 102 U. S. 691, 696; Bridge Company v. United States, 105 U. S. 470, 482; Miller v. New York, 109 U. S. 385, 392; Wisconsin v. Duluth, 96 U. S. 379; Willamette Iron Bridge Company V. Hatch, 125 U. S. 1. In Wisconsin v. Duluth (p. 383) it was said: "It is to be observed, as preliminary to an examination of the acts of the general government in the special matter before us, that the whole system of river and lake and harbor improvements, whether on the seacoast or on the lakes or the great navigable rivers of the interior, has for years been mainly under the control of that government, and that, whenever it has taken charge of the matter, its right to an exclusive control has not been denied. . And while this court has maintained, in many cases, the right of the States to authorize structures in and over the navigable waters of the States, which may either impede or improve their navigation, in the absence of any action of the general government in the same matter, the doctrine has been laid down with unvarying Opinion of the Court. uniformity, that when Congress has, by any expression of its will, occupied the field, that action was conclusive of any right to the contrary asserted under state authority. The adjudged cases in this court on this point are numerous." And in Willamette Iron Bridge Company v. Hatch (p. 12) the proposition was thus stated: "And although, until Congress acts, the States have the plenary power supposed, yet, when Congress chooses to act, it is not concluded by anything that the States, or that individuals by its authority or acquiescence, have done, from assuming entire control of the matter, and abating any erections that may have been made, and preventing any others from being made, except in conformity with such regulations as it may impose." It cannot be doubted, in view of the long list of authorities, for many more might be cited, that Congress has the power in its discretion to compel the removal of this lock and dam as obstructions to the navigation of the river, or to condemn and take them for the purpose of promoting its navigability. In other words, it is within the competency of Congress to make such provision respecting the improvement of the Monongahela River as in its judgment the public interests demand. Its dominion is supreme. But like the other powers granted to Congress by the Constitution, the power to regulate commerce is subject to all the limitations imposed by such instrument, and among them is that of the Fifth Amendment, we have heretofore quoted. Congress has supreme control over the regulation of commerce, but if, in exercising that supreme control, it deems it necessary to take private property, then it must proceed subject to the limitations imposed by this Fifth Amendment, and can take only on payment of just compensation. The power to regulate commerce is not given in any broader terms than that to establish post-offices and post-roads; but, if Congress wishes to take private property upon which to build a post-office, it must either agree upon the price with the owner, or in condemnation pay just compensation therefor. And if that property be improved under authority of a charter granted by the State, with a franchise to take tolls for the use of the |