Middletown Valley, also historically known as Catoctin Valley, is a valley

Valley

In geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...

 in western Frederick County

Frederick County, Maryland

Frederick County is a county located in the western part of the U.S. state of Maryland, bordering the southern border of Pennsylvania and the northeastern border of Virginia. As of the 2010 Census, the population was 233,385....

 in the state of Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

.

Geography

It is bound to the west by South Mountain

South Mountain (Maryland and Pennsylvania)

South Mountain is the northern extension of the Blue Ridge Mountain range in Maryland and Pennsylvania. From the Potomac River near Knoxville, Maryland in the south, to Dillsburg, Pennsylvania in the north, the long range separates the Hagerstown and Cumberland valleys from the Piedmont regions of...

, to the east by Catoctin Mountain

Catoctin Mountain

Catoctin Mountain, along with the geologically associated Bull Run Mountains, comprises the easternmost mountain ridge of the Blue Ridge Mountains, which are in turn a part of the Appalachian Mountains range...

, to the south by the Potomac River

Potomac River

The Potomac River flows into the Chesapeake Bay, located along the mid-Atlantic coast of the United States. The river is approximately long, with a drainage area of about 14,700 square miles...

 and to the north by the convergence of South Mountain and Catoctin Mountain, south of Quirauk Mountain

Quirauk Mountain

Quirauk Mountain is the highest point on South Mountain. The peak is located in northeastern Washington County, Maryland. It lies just southwest of Fort Ritchie Military Reservation in the village of Cascade and about 1/2 mile southeast of the community of Blue Mountain...

. Geographically, it can be considered an extension of the Loudoun Valley

Loudoun Valley

The Loudoun Valley is a small, but historically significant valley in the Blue Ridge Mountains located in Loudoun County in northwestern Virginia in the United States.-Geography:...

 which lies below the Potomac in Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

. The valley derives its name from Middletown

Middletown, Maryland

Middletown is a town in Frederick County, Maryland, United States. The population was 2,668 at the 2000 census. Middletown is a small, rural community steeped in American history...

, the largest town in the Valley.

The use of the Catoctin Valley terminology was prevalent up through the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

 but afterwards was abandoned due to confusion between it and the northern portion of the Loudoun Valley also referred to as Catoctin Valley

Catoctin Valley

The Catoctin Valley is a small valley, geographically and culturally associated with the larger Loudoun Valley in Loudoun County, Virginia.-Geography:...

.