Most of these migrants to the USA were Ulster Scots (people of Scottish origin, often described in the USA as the 'Scotch-Irish') who have made an immense - and disproportionate - contribution to almost every aspect of American life.

They have been successful in many fields, notably in politics; education; religion; the military; the law; commerce, industry and technological innovation; journalism and publishing; music, the arts and entertainment.

Theodore Roosevelt described the quarter-million Scotch-Irish who had settled the frontier by 1800 as forming "the kernel of the distinctively and intensely American stock who were the pioneers of our people ...."

They did not look backward to the Old Country as so many 'hyphenated Americans' have done. Indeed, it has been argued that they were the first true Americans, owing allegiance only to their new homeland, its government and democratic institutions.

Before and after the Declaration of Independence these ambitious and determined people helped to shape the character of the United States; in so doing, they assimilated so enthusiastically and successfully that most of their descendants don't think of themselves as being anything other than Americans.

That's why the majority of today's US citizens - including many of the estimated 25 million who have Scotch-Irish ancestry - are unaware of the formative influence of the Ulster Scots on the American way of life in general and their remarkable contribution to the Presidency in particular.

Thomson's Flying Eagle

The story of Ulster's Presidential links begins with the Great Seal of the United States. This was designed in 1782 by Charles Thomson, an orphan emigrant from Upperlands, County Londonderry who became Secretary of Congress.

His flying eagle, with the motto he chose from a Latin recipe for a mixed salad Epluribus unum - Out of many, one - is the Presidential badge of office to this day (and is on every 25 cent coin and dollar bill in American purses and pockets).

Thomson penned the first draft of the Declaration of Independence before Thomas Jefferson elegantly refined the prose. John Hancock, whose kin were from County Down, was first to sign ( with a famous flourish) the final version which had been printed in Philadelphia by County Tyrone-born John Dunlap.

Dunlap, as publisher of the first American daily newspaper, the Pennsylvania Packet, has left an indelible imprint on the history of the American Press ; the printing shop where he served his apprenticeship.

Gray's in Strabane, welcomes tourists who follow the Ulster-American Heritage Trail across Northern Ireland.

There were at least five other Scotch-Irish signatories: Thomas McKean, Edward Rutledge, James Smith, George Taylor and Matthew Thornton. These delegates were associated with some of the scores of Ulster settlements already prospering by 1776.

The first publication of the text of the Declaration on this side of the Atlantic was in the Belfast News Letter ( founded 1737), the oldest surviving daily newspaper in the English-speaking world.

The Presidents of Ulster stock

Among the Presidents of Northern Irish origin are the only three Chief Executives in the history of the office who were first-generation Americans: Andrew Jackson, James Buchanan and Chester Alan Arthur.

Andrew Jackson

7th President 1829-37. He was born in the predominantly Scotch-Irish Waxshaws area of South Carolina two years after his parents left Boneybefore, near Carrickfergus in County Antrim. A heritage centre in the village pays tribute to the legacy of Old Hickory, the "People's President".

James Knox Polk

11th President 1845-49. His ancestors were among the first Scotch Irish settlers, emigrating from Coleraine, County Londonderry in 1680 to become a powerful political family in Mecklenberg County, North Carolina. He moved to Tennessee and became its Governor before winning the Presidency.

James Buchanan

15th President 1857-61. Born in a log-cabin in Franklin County, Pennsylvania, he cherished his origins: "My Ulster blood is a priceless heritage". The Buchanan family was originally from Deroran, near Omagh in County Tyrone where the ancestral home still stands.

Andrew Johnson

17th President 1865-69. His grandfather left Mounthill, near Larne in County Antrim around 1750 and settled in North Carolina. Andrew worked there as a tailor and ran a successful business in Greenville, Tennessee, before being elected Vice-President. He became President following Abraham Lincoln's assassination.

Ulysses Simpson Grant

18th President 1869-77. The home of his maternal great-grandfather, John Simpson, at Dergenagh, County Tyrone is the location for an exhibition on the eventful life of the victorious Civil War Commander who served two terms as President. Grant visited his ancestral homeland in 1878.

Chester Alan Arthur

21st President 1881-85. His election was the start of a quarter-century in which the White House was occupied by men of Ulster origins. His family left Dreen, near Cullybackey, County Antrim, in 1815. There is now an interpretive centre, alongside the Arthur Ancestral Home, devoted to his life and times.

Grover Cleveland

22nd and 24th President 1885-89 and 1893-97. Born in New Jersey and raised in New York, he was the maternal grandson of merchant Abner Neal, who emigrated from County Antrim in the 1790s. He is the only President to have served two terms with a break between.

Benjamin Harrison

23rd President 1889-93. His mother, Elizabeth Irwin had Ulster roots through her two great-grandfathers, James Irwin and William McDowell. Harrison was born in Ohio and served as a Brigadier General in the Union Army before embarking on a career in Indiana politics which led to the White House.

William McKinley

25th President 1897-1901. Born in Ohio, the descendant of a farmer from Conagher, near Ballymoney, County Antrim, he was proud of his ancestry and addressed one of the national Scotch-Irish Congresses held in the late 19th Century. His second term as President was cut short by an assassin's bullet.

Theodore Roosevelt

26th President 1901-04. His mother, Martha Bulloch, had Ulster Scots and Irish Hugenot ancestors who emigrated from Larne, County Antrim in May, 1729. No site has yet been established for the ancestral homestead, but Roosevelt's oft-repeated praise of his "bold and hardy race" is evidence of the pride he had in his Scotch-Irish connections.

Woodrow Wilson

28th President 1913-21. His Ulster roots were very strong and dear to him. He was grandson of a printer from Dergalt, near Strabane, County Tyrone whose former home is open to visitors. Throughout his career he reflected on the influence of his ancestral values on his constant quest for knowledge and fulfilment.

Richard Milhous Nixon

37th President 1969-74. His family connections, as with so many of his Presidential predecessors, were to County Antrim. The Nixon ancestors left Ulster in the mid-18th Century; the Milhous family ties were with Ballymoney and Carrickfergus

Tailpiece: Black Night at the White House

Another Ulsterman who occupied the White House - by means far removed from the democratic process - was Major-General Robert Ross of Rostrevor, County Down.

He commanded British troops who marched into Washington DC on the night of August 24th 1814, setting fire to what was then called the Executive Mansion, causing interior damage and blackening its Virginia freestone facade.

So distressed was President Madison's wife Dolley, who had just spent $26,000 granted by Congress decorating the place, that she is said to have insisted on having the smoke-stained exterior painted white.

It has remained white ever since, but it did not become officially known as The White House until Theodore Roosevelt had the name engraved on his stationery.

Compiled by John Trew writer/broadcaster on Ulster-American affairs.