314 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
per cent, can be irrigated. Of the arid portions of Nebraska and Kansas, it is difficult 
to make an estimate, as the rainfall will undoubtedly aid very materially, and the line 
of the arid region moves from east to west over a considerable distance, from one year 
to another. If entirely dependent upon irrigation it would be very small, as then- are 
few small streams, and the large ones would be quite fully used in Colorado. 
Of Western Texas but a very small proportion can be cultivated, probably not more 
than 3 per cent., as the whole area of the Staked Plains is irredeemable. 
Tabulating the above figures, we arrive at the following results, as the possible 
arable area of the arid region : 
ARABLE LAND. 
Per 
cent 
Square 
mile* 
10 
10, 450 

5,070 
15 
20,000 
5 
0,060 
5 
5,465 
10 
9,780 
8 
11,500 
7 
6, 040 
3 
3, 3U0 
6 
' 3,000 
5 
5, 000 
3 
3, 750 
C 4 
-n, i~, 
Utah 
California 
Wyoming 
Montana. . 
Idaho 
Nevada 
Oregon 
Dakota 
Texas 
That is to say, about one acre in sixteen can be redeemed. 
The amount of land at present in actual cultivation in the Western States and Terri- 
tories is estimated at 8,000,000 of acres. Of this fully one-half is in California, and 
of this area of 4,000,000 of acres, nine-tenths is cultivated without irrigation, leaving 
400,000 acres, or 625 square miles, as the total amount of land in the State under irri- 
gation. The last are the figures for 1879, from the report of the State engineer. Of 
the remaining 4,000,000 of acres, about 1,000,000 are in the State of Oregon and the 
Territory of Washington, and of that portion in Oregon nearly all is in the Willamette 
and other valleys, where the abundant rainfall precludes the necessity of irrigation. 
There is at present but very little irrigation in this State. 
The lands under cultivation in Eastern Dakota, in the Red River Valley, and the 
valleys of the Missouri, Dakota, Big Sioux, and other streams in the southeastern part 
of the Territory, may be estimated at 1,000,000 acres more. In this part of Dakota 
irrigation is not needed. The remaining 2,000,000 acres, or 3,125 square miles, are 
distributed among the remaining States and Territories in about the following pro- 
portion : 
Per cent. 
Colorado :J0 
Utah 20 
New Mexico 20 
Montana 10 
Idaho 6 
Nevada G 
Arizona 3 
Dakota (arid portion) 2 
Wyoming 2 
Texas (arid portion) 1 
It is unnecessary to say that these are but very rough estimates made in default of 
any definite information upon the subject. 
Out of a possible arable area, then, of nearly 90,000 square miles in the arid region, 
there is at present an extent of but 3,750 square miles under actual cultivation — a pro- 
