Frederick County Land Record Abstracts 1748-1778 (12 Volumes) Patricia A. Andersen. Deed records list many transactions besides deeds such as bills of sale, manumissions, estate sales and boundary disputes etc. These abstracts cover territory from Washington D.C. to Carroll County and all counties west.
Using these records several persons were found missing in the deed index due to damaged or missing pages. Check the records and you may find your ancestor was in the area after all. The books can be located at historical and public libraries or for purchase online.