I only have clues for you.I wonder if your William Ira is a grandson of this Nathaniel:
1. Nathaniel Alger, b. in Killingly, Windham, CT, (son of Nathaniel Alger and Margaret _____). He married Mary Owen.Nathaniel died in Richmond, Chittenden, VT."The first settlements along the south side of the Winooski River between the mouth of Huntington River at Jonesville and the village of Richmond, were made by Amos Brownson Jr., Matthew Cox, Jesse Green, William Douglas, Barney and Comfort Starr, Clement Hoyt, James and Peter Crane, James Hall, , Nathaniel and Asa Alger.(Hemenway, Vol. 1, 1867, page 844, column 2). At the time of the 1790 census, Asa and Nathaniel Alger were living in Huntington, VT.
The History of Royalton, Vermont (Lovejoy, 1911, p. 26) speaks of a Nathaniel Alger of Killingly, CT who bought a lot in 1783, selling it the next July.Is this the same Nathaniel Alger?
A Nathan Alger and family were warned out of Swanton at an unspecified date, along with Asa Alger and family.
2. i Nathaniel Alger, b. abt 1782 in VT.He married Mary _____, b. abt 1803 in VT,2 d. in Dunkirk, Dane, WI?.2Nathaniel died aft 1880 in Dunkirk, Dane, WI?.2Nathaniel Alger settled in Dunkirk, WI (Alger, 1876, page 17). In 1880, he is found in the 1880 census for Dunkirk; he was 98 years of age.
3. ii Joseph Alger.He married Amanda Wheeler, 7 Jan 1827 in Milton, Chittenden, VT.1
4. iii David Alger b. 21 Aug 1788. Settled in Methuen, MA
5. iv James Alger, b. abt 1792 in Richmond, Chittenden, VT.He married Charlotte Rice, b. abt 1797 in MA,3,d. 4 Oct 1851 in Sheldon, Franklin, VT?,3 bur: in Rice Cemetery, Sheldon, VT.James died 19 May 1869 in Sheldon, Franklin, VT,3 bur: in Sheldon Union Cem., Sheldon, VT.3(On-line datebase:NewEnglandAncestors.org, New England Historic Genealogical Society, 2003.
6. v Ira Alger, b. abt 1795 in US,d. in Canada East.Ira and Allen Alger were twins (A. Alger, 1876, page 18).In the 1871 census of Quebec, an Ira Alger is listed, age 76, born in the US, of Irish heritage. He was living in Brome, QC with wife Lydia, age 74, who was of German heritage and born in Quebec.Tentatively, this is the Ira Alger.
+ 7. vi Allen Alger.
8. vii Auel Alger.
9. viii Truman Alger, b. abt 1800, d. 6 Jun 1839 in Shipton or Melburne, QC,bur: in Ste. Anne's Church.
10. ix Leonard Alger.
7. Allen Alger, (1.Nathaniel1). d. in Canada East.
26. i James Alger, d. 22 May 1889 in Bury, QC?.James is only tentatively the son of this Allen Alger.Is this the James Alger who was living in Brome, QC at the time of the 1871 Canadian Census? He was age 50 and living with wife Mary, age 38 and six children.Both were born in Quebec.