It's interesting, in the 1880 census (b 1879 per 1920, but 1876 per 1930 census)(familysearch.org) there are only 20 Erswells total -- none in IL, but the majority in OH ... and I've seen your posts in that direction.
Who is GEO in Maine? George ERSWELL - U.S. Social Security Death Index Birth: 14 Oct 1903State Where Number was Issued: MaineDeath: Sep 1985
Did you also see the children were born in RI?(1913, 1914/6)
And then they were back in RI to be issued SSNs by the 1950s?Can you find a death on Wm in RI?
RAYMOND ERSWELL8 Jan 1913Oct 1986Newport, Newport, RI (ISSUED) ME (Before 195) 004-05-6189 ROSE ERSWELL10 Jan 1892Apr 1986Newport, Newport, RI (ISSUED) RI (1965 And 1) 038-32-6779 ROSE ERSWELL17 Oct 1916Jan 1985Newport, Newport, RI (ISSUED) ME (Before 195) 004-16-7228