Question: What is the name of the region that includes the cities Dover and Portsmouth, New Hampshire?

<P0-S0>  The region stretches 13 mi along the Atlantic Ocean from New Hampshire's border with Salisbury, Massachusetts to the Piscataqua River and New Hampshire's border with Kittery, Maine. <P0-S1>  The shoreline is generally very rocky and rough in nature, although a few sandy beaches have been created using jetties/groins, particularly in the towns of Rye and Hampton. <P0-S2>  The Seacoast Region stretches as far west as Epping. <P0-S3>  Portsmouth, the largest municipality and only city in Rockingham County, serves as the cultural and commercial hub of the region. <P0-S4>  Portsmouth has numerous historical landmarks and tourist attractions including Strawberry Banke, the Moffatt-Ladd House, the John Paul Jones House, and the Portsmouth Children's Museum, which moved to Dover in 2010. <P0-S5>  The Seacoast Region was the first area of the state to be permanently settled by Europeans in the early 17th century. <P0-S6> The Seacoast Region is the southeast area of the U.S. state of New Hampshire that includes the eastern portion of Rockingham County and the southern portion of Strafford County. <SEP> <P1-S0> Norfolk County, Massachusetts Colony was one of the original four counties created in the Massachusetts Bay Colony. <P1-S1>  The land was originally granted as separate from Massachusetts, but boundary disputes among the settlers led to their petitioning to join the colonial government to the south. <P1-S2>  The county was created by the Massachusetts General Court on May 10, 1643, when it was ordered "that the whole plantation within this jurisdiction be divided into four sheires". <P1-S3>  Norfolk County contained the settlements of Salisbury, Hampton, Haverhill, Exeter, Dover, and Portsmouth. <P1-S4>  It effectively encompassed all settlements from the Merrimack River, north to the Piscataqua River, and extending inland about a dozen miles. <P1-S5>  In 1680, the Province of New Hampshire was formally separated from Massachusetts, with Norfolk County forming the core. <P1-S6>  Massachusetts retained the northern bank of Merrimack River and the towns of Salisbury and Haverhill were added to Essex County. <P1-S7>  Hampton, Exeter, Dover, and Portsmouth were governed at two levels, town and province/colony, until 1769, when New Hampshire was itself divided into counties, so that Norfolk ceased to exist. <SEP> <P2-S0>  The population was 29,987 at the 2010 census, the largest in the New Hampshire Seacoast region. <P2-S1>  The population was estimated at 31,153 in 2016. <P2-S2> Dover is a city in Strafford County, New Hampshire, United States. <P2-S3>  It is the county seat of Strafford County, and home to Wentworth-Douglass Hospital, the Woodman Institute Museum, and the Children's Museum of New Hampshire. <SEP> <P3-S0> The Portsmouth, Great Falls and Conway Railroad (PGF&C) (later known as the Conway Branch of the Boston and Maine Railroad) is a former rail line between Rollinsford and Intervale, New Hampshire, in the United States. <P3-S1>  At Rollinsford, the line connected to other lines to provide service between the White Mountains and coastal cities such as Boston. <P3-S2>  At Intervale, it connected to the Mountain Division of the Maine Central Railroad. <P3-S3>  The rail line takes its name from the city of Portsmouth, near its southern terminus; the city of Somersworth (formerly known as "Great Falls"); and the town of Conway, near its northern terminus. <P3-S4>  Today, the infrastructure of the former PGF&C is owned by different entities, including the State of New Hampshire, the Conway Scenic Railroad, and the New Hampshire Northcoast Corporation. <P3-S5>  Some segments are still operated as freight or heritage railways, while other segments are being maintained as rail trails.