I looked for Leah Brenneman in York today and didn't find her. How do you know she married George Kling? There are many Brennemans in Lancaster. I wonder if that is where she is from. If She is from York an analysis of the census records says she must be the daughter of Daniel Brenneman of Codorus Twp,later North Codorus Twp or David of Codorus Twp later of Hopewell Twp/N. Codorus or Henry of Conewago Twp. Of course her father may have died soon after her birth or they may have moved into York from elsewhere.
Of interest is that David and Daniel Brenneman and Lawrentz Kling are in North Codorus Twp in the 1839 thru 1845 as shown in the tax rcords. They are also there before and after this period.