My practice has been to start locations with the town as given in the records, e.g. Gehrden. This is then followed by another name in parentheses, e.g. (Brakel), which is the current "official" town of which Gehrden might be considered a part. Höxter is the current Kreis, or county, in which all of these German locales are now located. Westfalen as a name has a centuries-long tradition, although the boundaries have changed over time.
I have been loose with my designations of these locales as "Germany." While there is a certain sense in referring to a large section of central Europe as Germany, politically there has not always been such a place.
Germany as the political entity we now recognize came into existence in the early 1870s, the time of the Franco-Prussian War. Prior to that, the same region was a collection of various forms of governments, some smaller, some larger, and none more powerful than Prussia. The region of what is now the eastern part of the Land of Westfalen (English: Westphalia) became -- seemingly against the desires of much of its population -- part of Prussia in 1815.
So it was that when he left without permission because he did not want to serve with the Prussian army, Johann Joseph Zengerling left Prussia. If he applied at any point for American citizenship, he first would have needed to renounce allegiance to Prussia (which, given his apparent feelings toward Prussia, would not have caused him any problems).
The Prussian government, needless to say, was not terribly pleased with these "secret emigrations." If a potential soldier was not found because he had left, punishment in the form of a fine would be levied against the remaining family members. Thus, whole families might leave together, and so it was with Johann Joseph and his parents, Franciscus Josephus Zengerling and Anna Maria Bense, and his siblings. Such may also have been the case for his future wife, Anna Hoppe, whom he married in 1859, in Newark, NJ, as there is a record of her brother, Bernard Hoppe, also leaving around the same time (this uncle was Bernard/Benjamin Singerling's baptismal sponsor as recorded in the church books of St. Mary's, Newark).
Now, mind, there may be a slightly different slant for this story. The 1900 census notes that Joseph Zengerling had arrived in the United States in 1840. That would seem a bit early, if Johann Joseph were the one who decided he didn't want to serve. Likely, his parents were the ones to decide they didn't want their sons being called up in a conscription. Given that a sister was born in New York around 1847, it seems pretty clear that the family arrived sometime between 1840 and 1847.
Prior to their emigration, the family had been living at house no.53 (in the old numbering system) in Natzungen. This house had been in the family for generations. According to the book, Natzungen und seine Einwohner in den letzten 300 Jahren (or, translated, Natzungen and Its Inhabitants in the Last 300 Years), by Dr. Hoppe, the owners can be traced as follows (for the one hundred year period ending in the 1840s or 1850s):

• Anna Maria Elisabetha Bense, with her husband, Franciscus Josephus Zengerling (who had come from nearby Gehrden), and their children, including Johann Joseph Zengerling; she perhaps inherited it from her parents...

• Anna Maria Catharina Schäfers and her husband, Heinrich Bense (a Korbmacher, or basketmaker, and a Leineweber, or linen weaver, who had come from nearby Dalhausen); she may have inherited it from her parents...

• Joannes Joseph Schäfers/Scheiffers, a Zimmermann, or carpenter, and his wife, Maria Agnes Rempe/Rempen; he possibly inherited it from his father (and his father's third wife, Anna Luisa or Lucia Deppen/Detten)...

• Johann Heinrich Schäfers/Scheiffers, whose first wife, Anna Eva Margaretha Pauls, seems to have inherited it from her parents, Johann Pauls and Anna Maria Wintermeyer.

As in Germany, the locations in effect "move" over time. Although Oto Comanzo did indeed leave Italy, the area had been part of the Kingdom of the Two Sicilies a generation or two earlier. And while Ariano Irpino is currently in the region of Campania, until this century it was Ariano di Puglia.
Although from the south of Italy, he had the name of Otto. For the longest time, we just assumed that he had had the misfortune of being processed at Ellis Island by someone whose Italian left so much to be desired that an Italian given name was mangled into a German one.
We, of course, were simply unfamiliar with southern Italian history, especially the centuries-long rule by Norman invaders. That may explain why so many of my cousins are fair-haired. And it explains why it is that one of the patron saints of Ariano Irpino is San Ottone. There never was a name-mangler at Ellis Island (at least in this case). Nonno had a perfectly good Italian name.
He was the third son and the third child in his family. He learned the skills of the bastaio, the maker of saddles (which are called varda in the Arianese dialect) from his father, and along with his brothers. He used those skills in America to earn his livelihood as a calzolaio or cobbler.
Family history on this side of the Atlantic claims that he made the mistake of falling in love with the same woman that an officer in his military unit loved, and then compounded that mistake by beating up the officer. He had to flee, of course. Perhaps, he was merely a bell' uomo as the family still in Italy recalls, a good-looking man, who liked singing and dancing, and didn't really want to take up the family trade. Or maybe, he just had to leave because there wasn't enough work in the area of Ariano.
In any event, he left Italy, and sailed to America, where cousins who had previously left acted as sponsors. He went back to Italy only once that we know. That was in 1930, the year of the terramoto, or earthquake. Some sixty-odd years later, we found a collection of photographs of people we had never seen. Luckily, I thought to bring them with me when I first went to visit his family in Ariano in 1995, as they recognized the faces and locales. They had been taken during this return trip of his.

The Scottish ancestors that I have found have been concentrated in two areas: the so-called Stewartry of Kirkcudbright (or Kirkcudbrightshire), now located in the region of Dumfries and Galloway, and the town of Paisley, located in Renfrewshire, west of Glasgow.
It would seem, to judge from the ones that I have been able to research, that these ancestors were largely the type that moved back and forth between Ireland and Scotland. Jane Graham, for example, who came with her husband and children to the States in the early 1870s, was probably born in Ireland, although she married in, and emigrated from, Scotland.
A good number of these moved about with the flow of employment and unemployment, and in the southwest corner of Scotland, that often centered upon the weaving industry. So, it was likely that when the Gargan's went from Ireland to Scotland at some point before the mid-1830s, it was in search of employment. It seems that Thomas Gargan (or Gerrigen, as he is noted in the 1841 census, or Gahagan, as his children are noted in the Latin baptismal records of the 1830s and 1840s, or Girgan, as the name is spelled on his wife's 1866 death certificate) moved to Gatehouse of Fleet in the Stewartry because of the mills that had been opened there at the end of the eighteenth century. The 1841 census notes that he is a "cotton spinner" and lived on (or at) Covengarden.
It has been noted that water-driven mills, such as operated at Gatehouse, were soon eclipsed by steam-driven mills as the Industrial Revolution gained ground. It might be supposed that Thomas Gargan and his wife, Isabella Carson, moved their family north to Paisley (sometime between 1856, when the last child, Andrew Kirk, was born in Gatehouse, and 1861, when they appear in the census taken in Paisley) so that they could find employment.
It may not have been terribly successful, however. Thanks to another's research, it is known that Isabella had to apply for poor law assistance in the early 1860s, at which point she noted that her husband was away (looking for a job, we might assume) and that both her parents and her in-laws were dead.
But the weaving industry was central. In the 1861 census, when they were living at 39 Back Sneddon Street in Paisley, the occupations for the various members of Thomas' and Isabella's family were as follows:

• Thomas, head of household, age 46, cotton spinner
• Isabella, wife, age 49, no employment noted
• John, son, age 25, cotton spinner
• Margaret, daughter, age 23, mill worker
• Thomas, son, age 20, cotton spinner
• Prudentia, daughter, age 18, cotton spinner
• William, son, age 16, cotton spinner
• James, son, age 14, cotton spinner
• Charles, son, age 10, student
• Andrew, son, age 4, student

Thomas, the 20-year old son in this census, married Jane Graham in 1864. They, and their children, followed the weaving and spinning trade across the Atlantic Ocean to New Jersey, where Clark, the big name in Paisley industry, had taken over a mill on the banks of the Passaic River in East Newark. Family history has it that he was brought over to become a supervisor at the mill. Whatever that particular truth, the Clark Thread Mill in East Newark featured prominently in the occupations of many family members for four generations.

The earliest ancestors of mine to reach America would have been the family of Franciscus Josephus Zengerling and Anna Maria Bense, probably some time in the 1840s (the 1900 census notes their son, Johann Joseph, claims to have arrived in 1840). The latest would have been my grandfather, Oto Comanzo, who did not arrive until the 1920s. In a way, the various family lines roughly echoed the broader ethnic trends of immigration: first, the Germans, then the Irish, and later on the Italians.
The various lines of Germans, Irish, and Scots came together in the city of Newark, New Jersey, throughout the course of the 1800s. It was an up and coming city in the nineteenth century, eventually becoming quite an industrial giant, although it had very quiet Puritan roots. Here are some Newark highlights culled from John T. Cunningham's Newark (revised and expanded edition, 1988):

• 18 May 1666: arrival of Connecticut Puritans according to tradition.
• "Probably not more than 700 or 800 people lived in the village of Newark in the 1730s."
• "Leather was Newark's prime industry from the start."
• Later considered the "father of industry" in Newark, Seth Boyden arrived in Newark in 1815.

• A census published in 1826 by town assessor Isaac Nicholls notes 8017 persons, 17 factories, 3 distilleries, 2 breweries, and 1 grist mill.

• St. John's, built in 1828, is the first Roman Catholic church.
• The Morris Canal is fully operational by 1832.
• Newark becomes an "official port of entry" in 1836 and can receive foreign ships.
• Whaling is an industry operating out of Newark in the 1830s and 1840s.
• Railroads began to be developed in the 1830s.
• The 1840 Census notes a population of 17202 persons.

• "Discovery of gold at Sutter's mill [in California] in 1848 turned men wild with greed and hope. Some two hundred Newarkers joined an estimated 50,000 fortune hunters who sailed from East Coast ports in 1848 and 1849."

• The land for St. Patrick's Pro-Cathedral had to be bought in secret in the late 1840s, because of anti-Catholic feelings in the general population.

• The 1850 Census notes a population of 38894 persons.
• The train bearing Lincoln's body passes through Newark on 24 April 1865.

• "By 1870 more than one thousand men and women worked for Clark Thread Company. Later, when the company opened additional buildings in East Newark, Kearny and Harrison, it hired thousands more."

• "By 1870, [Newark tanneries] produced 90 percent of all patent leather made in America."

• The 1880 Census notes a population of 136508 persons, the 1890 Census 181830, and the 1900 Census 246070 persons.

• The last horse-powered street cars ran in 1893.