What is the source to find the number of a chart for a specific geographical area?

The catalog for nautical charts serves as the primary source for locating the number of a chart corresponding to a specific geographical area. It contains detailed listings of all available nautical charts, including their titles, scales, and coverage areas. This comprehensive reference guides mariners in identifying the appropriate chart they need for navigation in a particular region.

Other resources may contain valuable navigational information, but they do not serve the same purpose for chart identification. The Nautical Almanac focuses on celestial navigation and astronomical data, while the Local Notice to Mariners provides updates and changes regarding maritime navigation but does not include a chart catalog. The US Coast Pilot offers descriptive information about navigation routes, hazards, and points of interest, yet it does not list chart numbers specifically for locations. Therefore, the catalog for nautical charts is the most reliable and directed source for chart numbers.