Complex sentence: Port Hudson was a small town on the east bank of the Mississippi, 13 miles upriver from Baton Rouge, Louisiana, at a point where the river makes the passage there a subject of anxiety to pilots even in daylight and in time of peace.
Split into simpler sentences: Port Hudson was a small town on the east bank of the Mississippi, 13 miles upriver from Baton Rouge, Louisiana. At a point there, the river takes a course which generates marked anxiety for pilots, even in daylight and in time of peace.