The Coast Guard will establish a Security Zone on the Chicago River (Main Branch) between mile marker 325.6 (point at which the Chicago River connects to the South Branch Chicago River) and 100 yards extending past the end of the Chicago River covering the area of the Federal channel within Chicago Harbor and the North Branch Chicago River between mile marker 325.6 (point at which the North Branch Chicago River connects to the Chicago River-Main Branch and the South Branch Chicago River) and mile marker 331.4 (end of navigation channel). This action is intended to protect spectators and dignitaries associated with the Democratic National Convention. During the enforcement period listed below, entry into, transiting, or anchoring within the Security Zone if prohibited unless authorized by the Captain of the Port Lake Michigan or a designated Coast Guard or U.S. Secret Service Representative.
Source: Federal Register USCG
Link: Security Zone; Chicago River (Main Branch), North Branch Chicago River, South Branch Chicago River, Chicago, IL