If so, what made them “different”?
For instance, it seems there aren’t too many Danes, Czechs (not to be confused with Slovaks) or Northern Italians in the New World.
There is a Danish-settled town in California called Solvang. There is an excellent museum there of the “Danish Experience” in settling in America.
As far as Czechs go, keep in mind that Czechoslovakia did not exist as a political entity until after WW I. My Father’s ancestors came from there and settled in the Chicago area, but then they were known as Bohemians (and I suppose there were Moravians and Slovakians as well).
Plenty of Italians from Veneto, Friuli and Piemonte migrated to the New World but many settled in Argentina and Brazil.
There is also an enclave of Danes in upstate New York. I am half Danish on my father’s side of the family and when his family came here in the 1920s they moved there to be near other Danish families.
I went to school with a kid whose dad was from Denmark and in academic situations I’ve been able to identify other Danish people from their names on their ID tags.
Most non-Danish people can’t identify my name as Danish and guess Eastern European based on my appearance, but once in college I was in an elevator and out of the blue some guy asked, “Are you Danish?” When I had a “???” reaction he pointed out that I was holding my student ID in a way that he could see my name.
ETA: I also knew two guys in college who were of Slovak ancestry. They weren’t at all related and didn’t know each other, but strangely they looked very similar. Same hair cut and color, same facial features, even same manner of dressing to an extent. Both American born.
The French. That’s one of the reasons why the French lost the battle against the English.
However, there are a lot of people of French Canadian background in the US. I know several. You could argue that this isn’t the same because they were actually immigrants from Canada, despite speaking French and identifying as people with a French culture.
In fact, the derogatory term for all central European immigrants, “bohunk,” comes from Bohemian. So at one time they were considered the “typical” immigrant from that region.
Well, most Europeans didn’t immigrate to the US 
Demographics who seem to have been attracted at various points include the poor, entreprenurial, religiously restricted, criminals and adventurers.
Maybe Danes and Northern Italians are mostly non-religious, law-abiding content employees …
If you don’t count Louisiana.
Its a bit of an odd suggestion I’ll grant you - but how about the English and Welsh?
Given the war of independence being essentially against an English controlled Britain would seem to put them off, while the growth of other parts of the British empire subsequently would seem to be far more accommodating.
And many of the Louisiana French are here because of a losing battle with the Brits. I’m reading about the Seven Years War/French-Indian War; the ethnic cleansing of Acadia was a sideshow.
Lots of Czechs moved to Texas, bringing polkas, beer & kolaches. In Houston, you can obtain boudin kolaches!
In reading about the Atlantic Slave Trade, it was noted that the Dutch had a problem populating their northern colony from the old country. Fewer Dutch than English were eager to leave for the New World. The Netherlands were big in the slave trade at the time, so they bought a bunch of workers. I doubt we’ve had a huge number of Dutch immigrants, the Pennsylvania Dutch actually being Deutsch…
There are lots and lots of Czechs here in Northeast Ohio. And Slovaks and Bohemians. My family is Slovak and Bohemian, my best friend’s family is Czech. Our heritage is far from rare around here.
The Czechs have a cottage community out here, the Czech cultural center and previously a social hall in Karlin Hall. They share a lot of this cultural stuff with local Slovaks. They share the Slavic Village area with Poles. History of Czechs in Cleveland.
Are there many Belgians outside of Belgium/France/England?
I can’t imagine there’s been many Sami migrants to the Americas. Before the second half of the 20th century they subsisted almost entirely on herding reindeers, so that tended to limit their options to where they were able to move on land.
One of those Bohemians liked the New World so much, he named a symphony after it.
No Northern Italians in the New World? Pick up a Buenos Aires or Montevideo phone book. Otherwise, Sicilians and Southern Italians were (are) poorer and therefore came in more prominent numbers, but people don’t exactly differentiate on the census. Lots of Northerners in California, too. My nona had a very stereotypical Ligurian name that doesn’t even show up in the top X US surnames, but mostly appears in Argentina and CA Central Valley. You may have heard of e.g. Domingo (Domenico) Ghirardelli, of chocolate fame.
Very useful website for Italian names: it has distribution of Italian surnames in both Italy and the US. It’s not in English but it’s easy to figure out.
Ha!
And Wikipedia’s page on Sami American. Including people like Renée Zellweger, Balto the Human, and… Renée Zellweger. The article confirms my thoughts: probably more than a few immigrants with some Sami ancestry, but hardly any full blooded or culturally Sami.
There are very few Crimean Tartars (or Tartars from any part of European Russia) in the United States.
Other than Armenians, there are very people from the Trans-Caucausus who have settled in the US. This includes Chechens, Azeris,Dagestanis,etc.
While there is a distinct Bulgar community in Toronto,Ontario there are relatively few of them in the US. Most are located in the New York City metro area, Chicagoland and Los Angeles.
And after all these years, the only reference to the Sami in mainstream American culture is via a derogatory nickname in a Cole Porter song.
Actually I think it’s a fair point that the English and Welsh would tend to emigrate to other parts of the British Empire - nothing to do with the war putting them off, it just makes more sense that you’d move somewhere that’s still part of ‘home’ than a foreign country, plus there were frequently incentives given for them to move to certain places (such as the £10 Pom, when, post WWII, Brits were encouraged to go to Australia with a cheap passage).
You were more apt to emigrate if you lived in southern Italy. The north was, and still is, the more wealthy portion of the country; except for those few who emigrated to South America, there was no economic incentive to move. An old friend of mine was part Italian/Swiss…I remember him saying his grandparents were considered a minority within the greater Italian emigrant community because they weren’t from the south.
There used to be an enclave of Scandinavians (mostly Sami and Swedish) in my area. They arrived back when the quarries were in full operation. Many of them were stonemasons. There are still a few descendants around, but the enclave itself has either mostly died out or they’ve gradually assimilated with the Irish majority.
The rule of emigrant thumb: If you didn’t have an economic or other overwhelming reason to emigrate, chances are you stayed put.