The Upper Choptank River encompasses all of the waters of the Choptank River and its tributaries upstream of a line beginning at a point at the east shore of the Choptank River at the MD Route 404 (Business) Bridge at or near Lat. 38° 53.345' N., Long. 75° 50.115' W., then running 357° (True) to a point, at or near Lat. 38° 53.422' N., Long. 75° 50.120' W. This area, unless otherwise regulated, has a speed limit all year of: 35-knots daytime; and 25-knots nighttime.