I've located who I believe to be the earliest ROWNEY name bearers in Bedfordshire OPR. The details are following, but there is a simple question at the end:
John ROWNEY with wife Judith who were having children in the parish of Langford from 1691-1711.
Mary ROWNEY who married Robert FORTESCUE (or FOSCUE) in Potton in 1686, they had two children there, then Mary was buried there in 1689.
Elizabeth ROWNEY ("wife of John ROWNEY") buried in Biggleswade in 1706.
Elizabeth ROWNEY married Henry HALL in 1708 in Biggleswade. They have three children there between 1709 and 1715.
Braunston (or Braumston) ROWNEY marr. Elizabeth HUCKLE in Sutton in 1723 and they have children there between 1723 and 1739.
Jonathan ROWNEY marr. Mary BIRD in Potton in 1729, then apparently remarries (Mrs Frances WAGSTAFF) in 1731 and they are having children in Potton up until 1740.
The naming of children suggests Jonathan and Braunston were related.
John ROWNEY marr. Elizabeth HEWITT in Blunham in 1719, they have a son in Sandy in 1721 and then John apparently dies and was buried in Sandy in 1725. Elizabeth is buried in Sandy as a widow in 1739.
Another John ROWNEY and an Elizabeth ROWNEY are both buried in Biggleswade in 1737. They are thought to have been the married son and unmarried daughter of John and Judith (above), but this is not certain.
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Looking at all of the above it seems entirely possible that a single ROWNEY family living somewhere around Biggleswade in the mid 1600's could be responsible for bringing the relatively uncommon ROWNEY surname to Bedfordshire. The parishes with known early ROWNEY presence in rough chronological order seem to be Potton, Langford, Biggleswade, Blunham (one marriage), Sandy, Sutton, Dunton, Northill, and Southill.
I was hoping that someone with access to records from the 1600's such as Poll Tax or Hearth Tax, may be able to check to see whether any ROWNEY families/households appear, and if so, where and how many? I'm not sure how the records are organized, so a search of the above parishes would hopefully be sufficient to answer the question, although a countywide result would obviously be more conclusive.
Any information at all on the very early ROWNEY families in Bedfordshire would be invaluable.
Many thanks and best wishes,
Marc Roberts