1840 United States Federal Census (Ancestry.com)Edit
In the 1840 United States Federal Census, Frederick (town), in Frederick County, Maryland, appears in Dorchester County, Maryland. The error likely stems from the alphabetical organization of Maryland's counties on the National Archives microfilm publication (M704) of the 1840 census. Frederick County follows Dorchester County in this alphabetical organization. There are 91 images included in "Maryland > Dorchester > Frederick." No part of Frederick (town) appears in its correct placement in Frederick County.