Looks like its also picked up a wiki page since my last post: Spancil Hill

Considine worked in Boston for two years or so before moving to California. In failing health, he wrote the poem in memory of the hometown he would not live to see again, and posted it to his young nephew in Ireland.[10] Michael Considine died in California in 1873 at the age of twenty-three. [wiki]

My browser settings/add-ons, the Clare Library and about half the wiki source pages won't play nice but seems the only difference is how many hands the poem passed through before finally coming to the nephew John.

Mailed to Ireland c.1870-1873 after Micheal’s move to California and before brother Patrick was married (1875) and son/nephew John was born (abt: November, 1875.) Michael passed c.1873(?) and Patrick passed just three years after in 1876 when John was about two years old and still much too young to read.

Caveat: No hard North American sources that I could locate this new go 'round either. No clue where those Boston/California dates for Micheal come from.(?)