MD: Frederick County
Population: 241,409 (2013)
County seat: Frederick
Colleges and Universities: Frederick Community College
Rivers: Monocacy River, Little Pipe Creek, Sams Creek
Frederick County was created in 1748 from parts of Prince George's County and Baltimore County.
In 1776, Frederick County was divided into three parts. The westernmost portion became Washington County, named after George Washington, the southernmost portion became Montgomery County, named after another Revolutionary War general, Richard Montgomery. The northern portion remained Frederick County.
In 1837 a part of Frederick County was combined with a part of Baltimore County to form Carroll County which is east of current day Frederick County.
The county has a number of properties on the National Register of Historic Places.