The Harbour Channel, Southern Anchorage is one of many possible overnight havens lying along the so-called Back Route from Marathon (and Moser Channel) to Key West. This anchorage lies near the point where the marked cut rounds Harbory Key Bank Light, and then skips along its way off the Keys’ northerly banks as you cruise to Key West.
Personally, I would only try to enter the Harbor Channel by using a GPS chartplotter. There’s a lot of unmarked shallow water nearby!
More about this anchorage at http://www.CruisersNet.net/89-harbor-channel-southern-anchorage-2
June 2009. More sheltered than one might think due to shallows. Holding good after trying a couple of spots. Enjoyed 41 mph breeze in middle of thunderstorm at night with no problem. Fair amount of current. Lots of grass collected in sea strainers for generator and air conditioning requiring cleaning once per day. Plenty of room. No issues for 52 foot cruiser with 5 foot draft. One of the better anchorages if you follow the ICW route on the Florida Bay side of the Keys from Marathon to Key West. No problem carring 5 foot draft on that route.