Complex sentence: The Mount Vernon Arsenal was a United States Army munitions depot, located on the Mobile River three miles west of Fort Stoddert, approximately 30 miles inland from the Gulf of Mexico near Mount Vernon, Alabama.
Split into simpler sentences: The Mount Vernon Arsenal was a United States Army munitions depot. It was located on the Mobile River three miles west of Fort Stoddert, approximately 30 miles inland from the Gulf of Mexico near Mount Vernon, Alabama.