In a nutshell, the common white potato, Solanum tuberosum, is native to South America, to the Andes Mountains of Peru, and was unknown in Europe until Spanish explorers took it back there in about 1570. It was an instant hit. Many European countries began to grow the potato, but the country that became most heavily dependent on the growing of the common white potato was Ireland, where the [primarily English] land-owners went overboard in the planting of it in the 18th century. Previous staple crops were abandoned in favour of the potato, and the spud soon became the staple food of Ireland, so much so that this South American plant acquired the name "Irish potato". In the 1840s, the fungal pest called potato blight took hold in Irish potato fields, causing the tubers to suffer a dry brown rot. Potato blight had no natural enemies in Europe, and consequently, it became virtually impossible to stop its spread. By the 1845-1846 season, blight had destroyed virtually the whole of the potato crop in Ireland. People lost not only their source of income but also the staple food they depended on for their survival. It is estimated that as a direct result of the Irish potato famine of 1845-1848, more than a million Irish people starved, and more than 1.5 million Irish people emigrated from the island, the vast majority of them choosing the USA as their destination.

Many Irish people headed for the USA with no idea of what awaited them there, especially the "first-wavers". They boarded ships headed for New York City, Boston or other East Coast ports and hoped for the best. When they arrived, many of them went no further and remained in these port cities, taking whatever work they could get. After a while, some of them prospered. Irish people in America wrote to their kinspeople back home telling them of the USA and of job prospects. Those who went to America in later waves often arrived in New York City or in Boston with a promise, however vague, of a job. Sometimes this job panned out, and sometimes it didn't. So they asked around for news of jobs going elsewhere, and soon they learned that manufacturers were hiring in a prosperous city less than 150 miles up the Hudson River from New York City, easily accessible by riverboat. That city was Troy.

Men could get jobs in heavy industry, and women could get jobs in service or in the thriving cottage industry of collar-making.

Troy owed its 19th-century success to its location. Situated at the head of the tidal, navigable portion of the Hudson River just below the confluence of the Mohawk River into the Hudson, the city was well placed to benefit from the long-awaited completion of the Erie Canal in 1825, placing Troy on the main water route from Lake Erie to New York City. Another canal of the New York State Barge Canal network was the Champlain Canal, linking Lake Champlain to the Hudson River; again, Troy was strategically placed right on this route linking Canada by water to New York City. Anything produced in Troy could be transported by barge to a large market to the south (New York City and beyond), to the west (the Great Lakes and beyond) and to the north (eastern Canada).

The other key advantage of Troy's location was the fact that both the Poesten Kill and the Wynants Kill (kill being a Dutch word for "creek") flowed down in a series of waterfalls over an escarpment from the heights of "Mount" Olympus and "Mount" Ida into the narrow Hudson River plain, providing an excellent source of water power for industrial activity.

One of the first industries to harness this water power was the Troy Iron and Nail Factory, founded in 1812 on the Wynants Kill, in what is now South Troy. It gave its name to the entire surrounding neighbourhood, which was known for many decades as "the Nail Factory". With two waterwheels providing the power to a pair of rollers, the factory rolled hot iron into rods to make spikes and nails. The spikes were used not only for railway construction but also for boatbuilding.

In 1821, the Scottish-born industrialist Henry Burden (1791-1872) became involved in the company, first as agent and then as manager. He had a knack for thinking up new foundry techniques and devices, and he soon parlayed the company into the Troy Iron Works. Over the next 50 years, the Troy Iron Works of Messrs. Burden & Sons grew into one of the most important companies of its type in the USA. This company made all types of iron products, not least horseshoes. It could make horseshoes much faster and much more cheaply than the village blacksmith could. Hamilton Child, in his Gazetteer and Business Directory of Rensselaer County, N. Y., for 1870-71, gives this description of the Troy Iron Works: "The upper works consist of the main building, containing the forge and rolling mill, 400 feet by 75 feet, built against the perpendicular face of the rock which forms the bank of the ravine. A stone structure, 46 feet by 130 feet, contains the horseshoe shop machines, while attached are other buildings containing the spike and rivet factory, the punching shop, the foundry, the machine shop etc. These works are driven by an immense over-shot wheel, 60 feet in diameter and 22 feet in length, with buckets six feet four inches in depth, equal to 1,000 horsepower. A single spike machine turns out 45 railroad spikes per minute. There are also 20 puddling furnaces. The machines for making horseshoes turn out 60 shoes each per minute. The nail holes are punched by another machine. Some idea of the immense business in this department may be had from the fact that during four years ending with 1868, the Burden works manufactured in round numbers 25,000 tons of horseshoes, or, at 1.5 pounds per shoe, over 33 MILLION horseshoes. The merchant iron from this establishment is of a superior quality." The workforce numbered about 1,500. This company was well known far and wide, for this waterwheel that Child described was the largest waterwheel in the USA and was probably the third-largest in the world at that time.

Rivalling Burden's Troy Iron Works was the Albany Iron Works, owned by Erastus Corning (1791-1872) and Erastus Corning, Jr. Despite the name, this industrial complex was not located across the river in Albany - it, too, was in Troy, and it, too, drew its power from the Wynants Kill, very close by the Burden works. Child, writing in 1870, gives this description of the Albany Iron Works: "In 1809, John Brinkerhoff, of Albany, erected a small foundry and rolling mill for converting Swede and Russia iron bars into plates. These plates were subsequently partially cut into nails, the nails being headed by hand. Brinkerhoff transferred these works to Corning, Winslow & Co., who enlarged and ran them for several years. The production in 1835 was 6.5 tons per day. The Works assumed their present name [Albany Iron Works] in 1837. The Works are designated as the 'Water Mill', the 'Steam Mill' and the 'Star Forge'. The first puddling was done in 1838. There are now [in 1870] 34 puddling furnaces. The manufactures consist of merchant iron, railroad chairs, car axles, rivets, spikes, nails, horseshoes etc. About 750 hands are employed at an expense of $250,000 per year.... The patent solid lip railroad chairs were invented here and have had an immense sale." Child indicates that the company's annual production was valued at $1.75 million worth of merchant iron, railway car axles, chairs etc.; $400,000 worth of rivets, spikes etc.; $40,000 worth of nails; and $40,000 worth of horseshoes.

At almost the precise moment that Irish immigrants began to arrive in the USA in large numbers, the Rensselaer Iron Works were started up in Troy in 1846, by Le Grand Cannon and his son Le Grand D. Cannon, along with Peter A. Burden. With a start-up capital of $100,000, this company was looking for workers at a time when demand for iron products was great and the existing iron works were operating at full capacity. There is little doubt that word got out far and near that the managers of the Rensselaer Iron Works were hiring. This company went on to manufacture railroad iron, merchant iron and steel, railroad axles etc., valued at some $2.5 million annually. The workforce here numbered between 500 and 600.

But, I hear you saying, 500 or 600 jobs is not enough. Far more than 600 Irish people came to Troy at about this time. This is true. Undoubtedly, far more Irish people came to Troy than the Rensselaer Iron Works could employ, and more than all the iron works put together could employ. Those lucky ones who got these jobs stayed and settled down. But why did those less lucky, who didn't get jobs in the big iron works, stay in Troy?

Well, these iron works had catapulted Troy into a major industrial city from what once had been a sleepy river port trans-shipping agricultural produce, flax and bricks from the hinterland nearby onto river barges for transit to New York City. Troy was absolutely booming in the 1840s. There was money there, and this money meant opportunities for purveyors of all sorts of services, from domestic service below stairs in large, prosperous households to shopkeeping to supply all sorts of luxury goods to those well off enough to buy them. Then, too, other manufacturing companies were thriving in Troy as well. There were jobs to be had in other industries, such as brush-making, begun as early as 1823; textile mills to process wool and flax from the surrounding hinterland as well as cotton from all over the world landed at New York harbor and brought upriver in barges; and precision instruments for civil engineers and surveyors (the W. & L. E. Gurley Company was known for its high quality and supplied most of the USA). In 1824, an endowment from the patroon Stephen Van Rensselaer (1764-1839) had made possible the founding in Troy of the institution that was to grow into the Rensselaer Polytechnic Institute (RPI). This is now, and has been since its earliest days, one of the most respected technological universities in the country. RPI assembled in Troy some of the best engineering minds in the USA, right in the midst of existing industrial enterprises that had a high demand for their services to assure continued growth.

Most important among these other industries, though, was the collar industry. It was in Troy in 1827 that the detachable shirt collar had been invented. This innovation led to two new industries in Troy: the manufacturing of the collars (as well as of detachable cuffs and dickeys) and the laundering of the collars. Early on, these collars were sold in shops in Troy, and demand was great enough that these shops could not supply enough to meet that demand. One shop soon set up a workshop to ensure a regular supply, but this, too, could not meet all the demand. Family and friends were persuaded to make the collars, and this led to the custom of "outsourcing". In "outsourcing", rather than employ a staff in-house to make the collars, the entrepreneur contracted what today we would call "freelancers" to supply the collars and paid them "piecemeal", for however many collars they supplied. Most of the Irish women who arrived from the late 1840s onwards already had formidable sewing skills, and this working arrangement suited them well because they could continue their traditional role as housewife and mother while sewing detachable collars to supplement the family income. This practice of "outsourcing" was already well entrenched in the collar industry before one small workshop was set up in 1851 in Troy that would grow into the giant shirt and collar manufacturer Cluett, Peabody & Company, makers of "Arrow"-brand shirts. Cluett, Peabody & Co. had large factories in the traditional sense, but it suited the company to continue the practice of "outsourcing" as well.