The following are the approximate lengths of the shore lines of the United States on the Great Lakes and connecting rivers as estimated by the United States Lake Survey in 1920:

The Canadian shore line is 3,774 miles. The shore line of Lake Michigan, which is entirely in the United States, is 1,304 statute miles.

GEOGRAPHIC CENTERS OF THE CONTINENTAL UNITED STATES AND OF THE SEVERAL STATES.

The geographic center of an area may be defined as that point on which the surface of the area would balance if it were a plane of uniform thickness, or in other words the center of gravity of the surface. The exact position of the center of each State can not be determined from the data available, but the following approximate positions are sufficiently exact for ordinary purposes. In finding the centers of the States islands adjacent to their coast lines and large bodies of water on their boundaries have been excluded. The center of the continental United States (exclusive of Alaska) is in the eastern part of Smith County, Kans., latitude 39° 50′, longitude 98° 35'.3

U. S. Coast and Geodetic Survey Special Pub. 47, p. 57.

Alabama.

State.

Alaska (including islands).

Geographic centers of the States.

County.

Chilton..

Arizona..

Arkansas.

California.

Colorado.

Connecticut.

Yavapai.
Pulaski.
Madera..
Park.
Hartford.

Locality.

12 miles southwest of Clanton.
95 miles south of Fort Gibbon.
45 miles southeast of Prescott.
12 miles northwest of Little Rock.
35 miles northeast of Madera.

30 miles northwest of Pikes Peak.
At East Berlin.

11 miles east of Dover.

Near corner of Fourth and L streets, NW 12 miles west of north of Brooksville,

18 miles southeast of Macon.

24 miles south of west of Challis.

28 miles northeast of Springfield.

14 miles west of north of Indianapolis.

5 miles northeast of Ames.

15 miles northeast of Great Bend.

3 miles west of north of Lebanon.

3 miles southeast of Marksville.
18 miles north of Dover.

3 miles east of Collington.

In northern part of city of Worcester.
5 miles west of north of Cadillac.
10 miles southwest of Brainerd.

9 miles north of west of Carthage.
20 miles southwest of Jefferson City.
12 miles west of Lewistown.

10 miles northwest of Broken Bow.
24 miles southeast of Austin.
3 miles east of Ashland.

5 miles southeast of the State capitol.
12 miles west of south of Willard.
6 miles east of south of Oneida.
10 miles northwest of Sanford.
25 miles northeast of Washburn.
25 miles east of north of Columbus.
8 miles north of Oklahoma City.
25 miles east of south of Prineville.
24 miles southwest of Bellefonte.
1 mile west of south of Crompton.
13 miles southeast of Columbia.
8 miles northeast of Pierre.

5 miles northeast of Murfreesboro.

20 miles northeast of Brady.

3 miles north of Manti.

3 miles east of Roxbury.

11 miles south of east of Amherst.

10 miles south of west of Wenatchee.
4 miles east of Sutton.

9 miles southeast of Marshfield.
58 miles north of east of Lander.

EXTREME AND MEAN ALTITUDES OF THE STATES AND

PRINCIPAL POSSESSIONS.

Some of the altitudes in the following list are approximate only. Exact figures can not be obtained until a complete survey has been made of each area.

Extreme and mean altitudes in the United States-Continued.

In order to compare the altitudes in the United States with those in foreign countries the following list is given, but many of the figures are only approximate.

This figure for the altitude of Mount Everest is based on computations made in 1852. A more recent computation of the old observations and of six new ones gives a mean of 29,141 feet. It is estimated that the true height may be from 40 to 100 feet greater than 29,141. For a discussion of this matter see HowardBerry, Lt. Col. C. K., Mount Everest reconnaissance, 1921, pp. 10-12, New York and London, Longmans Green & Co., 1922.

LIMITS OF THE CONTINENTAL UNITED STATES.

The limiting latitudes and longitudes of the mainland of the United States, exclusive of Alaska, are as follows:

Cape Sable, Florida, is in latitude 25° 07', longitude 81° 05'. The extreme south point of Texas is in latitude 25° 50′, longitude 97° 24'. The Lake of the Woods projection extends to latitude 49° 23′ 04.5", at longitude 95° 09' 11". The easternmost land is West Quoddy Head, near Eastport, Maine, in longitude 66° 57', latitude 44° 49'. Cape Alava, Washington, extends into the Pacific Ocean to longitude 124° 44', at latitude 48° 10′.

From the south point of Texas due north to the forty-ninth parallel the distance is 1,598 miles. From West Quoddy Head west along the parallel to the Pacific Ocean the distance is 2,807 miles. These distances are computed to mean sea level.

The length of the Mexican boundary from the Gulf of Mexico to the Pacific Ocean is approximately 1,744 miles. The length of the northern boundary, excluding Alaska, is 3,980 miles. (See p. 220 for length of coast lines.)