Hello I Am Looking for Any Information Regarding Marriage Records from Around 1790 1791 IN the Cumberland Maryland Area on Priscilla Slagle John O...

A daughter of Jacob Slagle, Priscilla's family lived in Hampshire County, Virginia, & then she & John O'Harra (possibly o'Hara, O'Harrow) supposedly married in Cumberland, Maryland around 1790. I've been looking for a while for any information regarding her marriage & the birth of her daughter Mary Polly O'Harra around 1791 without much luck. I truly appreciate any help. Sandra