The U.S. Coast Guard says ships can't drop anchor in the Straits of Mackinac unless they have permission.
The area between Michigan's two peninsulas has an oil pipeline, known as Line 5, as well as electrical cables.
The Coast Guard says the goal is to prevent damage to the lines from anchors. There is an exception to the no-anchor zone in case of emergency.
The policy starts Oct. 31 and covers ships that are at least 131 feet long. The rule was published Oct. 1 in the Federal Register.
The Legislature is working on a similar ban. Gov. Rick Snyder in May approved an emergency rule barring anchors in the waterway, after a tugboat anchor struck oil and electrical lines and caused an insulation spill.