The location of this fort was a strategic point along the water route that led from New York City via the Hudson River, across Lake George and Lake Champlain to Montreal and Quebec City. French, British and American forces all sought to control this water route as the key to control of New England and much of the eastern seaboard. Some of the forts along this route changed hands several times over the course of two major wars, the French & Indian War and the Revolutionary War.
Lake Champlain, Lake George and the Hudson River were not connected by navigable waters and portages were require to move supplies and boats from one to the next. These portage points had been used for centuries by natives and were well defined. The first portage or "Great Carrying Place" as it was known, was from the Hudson River to Wood's Creek by the present day town of Fort Ann for access to Lake Champlain and Lake George. The second portage was from the north shore of Lake George to Lake Champlain around the falls of the La Chute River. These land crossings were very strategic to blocking any invading force going north or south, there were not any other options if a large force was involved.
The major fortifications along this water route included the fortifications at Crown Point (Fort St. Frederic, Fort Crown Point), the fortifications below Crown Point (Fort Carillon, Fort Ticonderoga), the fortifications at the south end of Lake George (Fort William Henry) and the fortifications at the head of navigation on the Hudson River (Fort Edward (1), etc). Further down the Hudson the Revolutionary War fortifications at Fortress West Point (Fort Constitution , Fort Clinton) also played an important role.