Lake Champlain
Forts at Ticonderoga and Crown Point (Fort St. Frederic) controlled passage of the lake in colonial times.  Important battles were fought at Ticonderoga in 1758 and 1777.  A important naval battle was fought in 1776 at Valcour Island: in the Battle of Valcour Island, Benedict Arnold delayed British ships enough to prevent the fall of these forts until the following year, allowing the Continental Army to grow stronger and allowing the later victory at Saratoga.