Some records suggest the Selby family may have come from Haddon, Huntingdon, England. There was a Skeffington SELBY there in the 1690s, married to “Elizabeth” and they had several children in that parish. A Skeffington SELBY died in Elton, Huntingdonshire in 1717, and another in 1723. One of them might be the Skeffington SELBY who was born in 1664 in Elton.

Children of Skeffington & Elizabeth Selby, Haddon, Huntingdonshire, England:
William bap. 19 Apr 1692, d. 20 Apr 1692
Alice bap. 18 Apr 1693
John b. 3 Jul 1695, bap. 21 Jul 1695, d. 3 Sep 1695
Mary bap. 10 Aug 1696
Thomas, bap. 3 Nov 1698
Ancestry.com

A John SELLBY [sic] was baptized 15 Sep 1722 in Elton, Huntingdonshire, to Thomas & Elizabeth Selby.

A Skeffington Selby was baptised 5 Feb 1722, in Elton, Huntingdon, to Thomas & Elizabeth Selby. FHL Film Number: 1040982 (same film for “John SELLBY)”. Could this have been Skeffington’s eponym?

Note how close Elton is to Oundle. Elton today is part of Cambridgeshire. Haddon is also in Cambridgeshire and only a little bit east of Elton. Haddon & Elton are adjacent parishes.

A John SELBY was buried in Elton in 1797. Unfortunately the record transcription does not give his age at death (nor does the National Burial Index For England & Wales).
[5758]

A John SELBY was baptised 11-DEC-1645, Elton, Huntingdon, to John & Sarah Selby.
Ancestry.com. England, Select Births and Christenings, 1538-1975

A Sarah Ann SELBY was buried in Oundle on 20-NOV-1814, age 2; so born circa 1812 (this record appears on the same page as Source[5683] [5383] ), so this child could have been a grandchild of John.