Ha, Gallicia must be like Ireland. 
“Ride Captain Ride” - The Blues Image
Van Dieman’s Land (U2 does a version) for people transported to Tasmania, which is now part of Australia.
I’ve been told that The Parting Glass is an Immigrant song, about your “American Wake” - the last night out with your mates before you move to America - but I’ve always heard it sung as a funeral song.
Black 47 do a lot of songs on the theme, both modern and historical - but their songwriter is an Irish immigrant in NYC, so that’s pretty par for the course.
Woody Guthrie=“Deportees (Plane Wreck at los Gatos Canyon)”
The entire album “Harbour of Tears” by Camel is about Irish emigrating to the US.
And there’s also “Send 'em Back” by the Foremen. 
“California Snow” by Dave Alvin
Letter from America - The Proclaimers (Scottish emigration to America)
Across the Borderline - Ry Cooder (performed here by Willie Nelson) (On the surface, a song about crossing the Rio Grande into the US, though arguably, crossing the river is a metaphor for dying in this song.)
Englishman in New York by Sting, about Quentin Crisp?
Ah, here we go:
Across the Borderline - Ry Cooder
There’s a really nice cover of this song by John Hiatt and Flaco Jiménez on the CD Partners.
The Proclaimers ‘Letter From America’ compares the 1980’s economic migration from Scotland to the Highland Clearances, where Scots were forced off their land to make way for sheep.
Smile In Your Sleep is solely about the Clearances.
Erin Go Bragh is about Lowland Scots discrimination against Irish and Highland migrants.
The leaving of Liverpool - Leaving of Liverpool (New Version)
Cliffs of Doneen - The Cliffs of Doneen
From Clare to here - From Clare to Here
Great site often with tune
Does moving about within a country count? If os, then what about “O Shenandoah” which is about leaving Virginia for the West. Or leaving a girl in Virginia for the West. Or an Indian maiden who’s father won’t let you take her with you on your way out West.
Or something. Depends upon whose lyrics you pick.
and shit.