Belknap County	001	Laconia	1840	Parts of Merrimack County and Strafford County.	Jeremy Belknap (1744.1798), early New Hampshire historian.	60,641	401 sq mi
(1,039 km2)	State map highlighting Belknap County
Carroll County	003	Ossipee	1840	Part of Strafford County.	Charles Carroll of Carrollton (1737.1832), the last surviving signatory of the United States Declaration of Independence.	47,285	934 sq mi
(2,419 km2)	State map highlighting Carroll County
Cheshire County	005	Keene	1769	One of five original counties.	English county of Cheshire.	75,909	708 sq mi
(1,834 km2)	State map highlighting Cheshire County
Coos County	007	Lancaster	1803	Part of Grafton County.	An Algonquian word meaning "small pines".	31,212	1,801 sq mi
(4,665 km2)	State map highlighting Coos County
Grafton County	009	North Haverhill	1769	One of five original counties.	Augustus Henry Fitzroy, 3rd Duke of Grafton (1735.1811), a Prime Minister of Great Britain (1768.1770).	89,320	1,714 sq mi
(4,439 km2)	State map highlighting Grafton County
Hillsborough County	011	Manchester and Nashua	1769	One of five original counties.	Wills Hill, 1st Marquess of Downshire (1718.1793), known in America as the Earl of Hillsborough, who served as the first Secretary of State for the Colonies.	406,678	876 sq mi
(2,269 km2)	State map highlighting Hillsborough County
Merrimack County	013	Concord	1823	Parts of Hillsborough County and Rockingham County.	The Merrimack River.	147,994	934 sq mi
(2,419 km2)	State map highlighting Merrimack County
Rockingham County	015	Brentwood	1769	One of five original counties.	Charles Watson-Wentworth, 2nd Marquess of Rockingham (1730.1782), a two-time Prime Minister of Great Britain (1765.1766, 1782).	301,777	695 sq mi
(1,800 km2)	State map highlighting Rockingham County
Strafford County	017	Dover	1769	One of five original counties.	William Wentworth, 2nd Earl of Strafford (1626.1695), an English noble who owned colonial lands.	126,825	369 sq mi
(956 km2)	State map highlighting Strafford County
Sullivan County	019	Newport	1827	Part of Cheshire County.	John Sullivan (1740.1795), the third and fifth governor of New Hampshire (1786.1788, 1789.1790).	42,967	537 sq mi
(1,391 km2)	State map highlighting Sullivan County