Navigational chart collection

The Navigational Charts Collection documents the history of this form of cartographic aid to mariners on the Great Lakes. Approximately 2,600 items in the collection date from 1849 to 2002. These charts were produced by a variety of sources in the United States and Canada. Most items were drafted by the United States Lake Survey, the United States National Oceanographic and Atmospheric Administration, the Canadian Hydrographic Service, and the Canadian Department of Fisheries.

Included in this collection are charts for entire lakes for each Great Lake, for connecting waterways, and for subregions (Lake Erie-West End) in the lakes. Individual harbors are charted, as is the St. Lawrence River. Other locations within the Great Lakes Basin are also represented through charts for the Border Lakes between Ontario and Minnesota. Charts for the New York State Barge Canal system are also present. Scattered Atlantic Coast and Mississippi Valley charts appear in small quantities.

Most collection charts were designed for standard navigational purposes. Others were prepared as bathymetric or morphometric guides to the underwater geology of the lake floors. Some charts focus on shoreline development patterns

The charts are arranged numerically by catalog number under each lake, river or canal. When searching for charts on an area on the boundary between two bodies of water, researchers should consult the list of charts for both areas to see all potentially useful charts. For example, the mouth of the Detroit River is covered by both Detroit River and Lake Erie charts. Items in this chart collection reflect polyconic and mercator projections. Variations on these two main projections include universal transverse mercator, transverse mercator, and Lambert conformal conic formats.

A complete list of individual charts, including number, date, and issuing agency is linked to this finding aid in the External Documents section.