Detailed coverage of Chicago Harbor. OceanGrafix provides mariners with the most up-to-date, NOAA-approved nautical charts ever offered. Charts are printed only after an order has been received, ensuring the most up-to-date information. All Notice to Mariners corrections are applied. Meets U. S. and international carriage requirements for commercial vessels. U. S. Coast Guard approved, Scale: 1:15,000, Dimensions/Size (inches): 34.86 x 41.58