Upward of one hundred and fifty thousand miles of irrigation canals, with reservoirs and supplementary works, have been built at a cost of more than six hundred million dollars. These projects are distributed through the States of Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington and Wyoming. The most notable among them are: the Truckee-Carson Canal and Reservoir, in Nevada; the Minidoka project, in southern Idaho; that of the Uncompahgre Valley, in Colorado; the Roosevelt Dam, in the Salt River Valley, Arizona; the Klamath Reservoir, on the Oregon-California boundary; the Boisé project, Idaho; that of Yuma, on the Arizona-California boundary; North Platte, on the Nebraska-Wyoming boundary; and the gigantic Elephant Butte Reservoir, in New Mexico—the second largest in the world.

Political Divisions.—Under its present organization the United States comprises fifty-one political divisions. Of these forty-eight are states enjoying the full privileges afforded by the federal constitution. The three territories—Alaska, Hawaii and Porto Rico—all are organized but not yet admitted to statehood. The Philippines have a modified territorial government.

(See [Tables] appended.)

It is worthy of remark that the center of population advanced westward during the ten decades since 1790 in a nearly uniform line along the thirty-ninth parallel of latitude.

THE CENTER OF POPULATION

Census
Year
Approximate Location by Important TownsFrom Point
to Point
in Direct
Line[9]
1790Twenty-three miles east of Baltimore, Md....
1800Eighteen miles west of Baltimore, Md.40.6
1810Forty miles northwest by west of Washington, D. C.36.9
1820Sixteen miles north of Woodstock, Va.50.5
1830Nineteen miles west by southwest of Moorefield, W. Va.[10]40.4
1840Sixteen miles south of Clarksburg, W. Va.[10]55.0
1850Twenty-three miles southeast of Parkersburg, W. Va.[10]54.8
1860Twenty miles south of Chillicothe, Ohio80.6
1870Forty-eight miles east by north of Cincinnati, Ohio44.1
1880Eight miles west by south of Cincinnati, Ohio58.1
1890Twenty miles east of Columbus, Ind.48.6
1900Six miles southeast of Columbus, Ind.14.6
1910In the city of Bloomington, Ind.39.0

[9] Movement in miles during preceding decade.

[10] West Virginia formed part of Virginia until 1860.

Public Lands.—The United States originally owned nearly all the area of the states, with the exception of the original thirteen. Homesteads have been given, or sold at a nominal price, to all bona fide settlers. Vast areas have been given to railroad companies and in aid of education. The country’s Indian wards have been provided with ample reservations. The government has established great national parks, and it has reserved more than seventy-two thousand square miles of forest land.

The following tabulations give numerous important facts concerning the states and territories: