I. A N. W. central county of Iowa, intersected by the Des Moines river and its W. branch; area, 576 sq. m.; pop. in 1870, 2,596. It has an undulating surface and a fertile soil. There are quarries of good building stone. The chief productions in 1870 were 59,101 bushels of wheat, 107,950 of Indian corn, 60,316 of oats, 12,416 of potatoes, 83,985 lbs. of butter, and 9,133 tons of hay. There were 999 horses, 1,021 milch cows, 1,614 other cattle, and 1,393 swine; 1 saw mill, and 2 flour mills. Capital, Dakota City. II. A N. W. county of California, bordering on the Pacific, and drained by Eel, Mad, and Bear rivers, and other streams; area, 2,800 sq. m.; pop. in 1870, 6,140. Humboldt bay lies near the N. W. corner, and Cape Mendocino, the westernmost point of the state, projects into the Pacific near the centre of the coast line. The surface is mountainous, and mostly covered with forests of redwood, pine, spruce, etc, which attain an enormous size. The bottom lands are fertile, but lumber is the chief source of wealth. Petroleum has been found in the S. part. The streams swarm with salmon.

The chief productions in 1870 were 32,284 bushels of wheat, 137,022 of oats, 31,907 of barley, 54,316 of peas and beans, 372,924 of potatoes, 112,580 lbs. of butter, 51,867 of wool, and 7,426 tons of hay. There were 4,329 horses, 5,691 milch cows, 12,056 other cattle, 12,660 sheep, and 10,050 swine; 3 manufactories of carriages, 1 flour mill, and 8 saw mills. Capital, Eureka. III. A N. W. county of Nevada, bordering on Oregon; area, 19,000 sq. m.; pop. in 1870, 1,916, of whom 220 were Chinese. The surface is generally mountainous, the E. portion being occupied by the Humboldt range. Humboldt, Reese, and Quins rivers, and other streams that lose themselves in "sinks," or lakes without outlet, water portions of the county. There are several lakes in the W. part. On Humboldt river and in Paradise and other valleys is some arable land, and the hills afford grazing; but the chief wealth is in the silver mines, which are mostly S. of the Humboldt river. Gold, copper, and lead are also found. By the census of 1870, 14 mines were returned, of which 12 were of silver, 1 of gold, and 1 of lead. There were 10 quartz mills, all except one for the production of silver. It is traversed by the Central Pacific railroad.

The chief productions were 4,419 bushels of wheat, 30,209 of barley, 5,504 of potatoes, and 2,219 tons of hay. There were 365 horses, 2,186 cattle, 700 sheep, and 786 swine. Capital, Unionville.