Coos County (with two syllables) is a county in the U.S. state of New Hampshire, including the whole of the state's northern panhandle. The two-syllable pronunciation is sometimes made visible using diaeresis, notably in the Lancaster-based weekly newspaper The Coös County Democrat and on some county-owned vehicles.
Coos has the largest area of the New Hampshire counties, but as of 2000, by far the smallest population, at 33,111. The county seat is Lancaster. Major industries are forestry and tourism, with the once-dominant paper-making industry in sharp decline.
Coos County is part of the Berlin, NH–VT Micropolitan Statistical Area.
During the American Revolutionary War two units of troops of the Continental Army — Bedel's Regiment and Whitcomb's Rangers — were raised from the settlers of Coos. From the Treaty of Paris of 1783 until 1835 the boundaries in the northern tip of the county (and New Hampshire itself) were disputed with Lower Canada (which was soon to become part of the Province of Canada), and for some years residents of the area formed the independent Republic of Indian Stream.
In the 1810 census there were 3,991 residents, and by 1870 there were nearly 15,000, at which point the entire county was valued at just under $USD 5 million, with farm productivity per acre comparing favorably with that of contemporary Illinois. Other early industries included forestry and manufacturing, using 4,450 water horsepower in 1870.
Much of its mountainous area is reserved as national forest, wilderness, state parks and other public areas. These encompass most of the northern portion of the White Mountains, including all the named summits of the Presidential Range (though one, Mt. Webster's, lies about 200 feet from the county line). Mt. Washington's peak is the highest in the Northeast.

There were 13,961 households out of which 28.10% had children under the age of 18 living with them, 52.30% were married couples living together, 8.80% had a female householder with no husband present, and 34.40% were non-families. 28.80% of all households were made up of individuals and 14.10% had someone living alone who was 65 years of age or older. The average household size was 2.33 and the average family size was 2.82.
In the county the population was spread out with 22.80% under the age of 18, 6.30% from 18 to 24, 26.70% from 25 to 44, 25.70% from 45 to 64, and 18.50% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 95.60 males. For every 100 females age 18 and over, there were 92.60 males.
The median income for a household in the county was $33,593, and the median income for a family was $40,654. Males had a median income of $32,152 versus $21,088 for females. The per capita income for the county was $17,218. About 6.80% of families and 10.00% of the population were below the poverty line, including 10.70% of those under age 18 and 12.50% of those age 65 or over.
* In New Hampshire, locations, grants, townships (which are different from towns), and purchases are unincorporated portions of a county which are not part on any town and have limited self-government (if any, as many are uninhabited). Villages are census divisions of towns or cities, but have no separate corporate existence from the municipality they are located in.
(Compiled from Radiostationworld.com)
Coos County is part of the Portland-Auburn DMA. Cable companies carry Fox (WPFO), ABC (WMTW), CBS (WGME), NBC (WCSH) and select Burlington, Vermont and Portland stations.