Three Mile Cruising Guide: 
Navigating the Harbor 
& Important Waypoints

In this section we will describe to you everything you need to know while navigating inside and outside Three Mile Harbor.  While the harbor is quite large it has a narrow entrance with a long sandbar inside the harbor.

This Navigation section is broken down into four section; Approaching the Harbor, Inside the Harbor, Hazards and Important Waypoints.

Approaching the Harbor....

If you are approaching Three Mile Harbor from the east you will need to be cautious will passing Hog Creek Point.  You should remain a quarter to half a mile off shore to avoid hitting any rocks near the surface.  Lionhead rock is located just north of the point and lies just beneath the surface during low tide. There are also several other large rocks off the eastern side of Hog Creek Point. 

As you can see from the chart on the left, the waters outside Three Mile Harbor are very open and deep.  As you approach the channel, the depth drops off significantly outside the channel.  There is a Red and White mid channel marker approximately half a mile from the entrance to harbor indicating the channel.  Outside the channel near the beaches, the water is approximately 4-5 feet deep.  There is a public beach and jetty located on the eastern side of the channel.  There is enough depth on the western side for some boats to anchor, but it may be very rough with all the traffic from local boats.  See our anchorage section for more details.  

As you enter the harbor you will pass through two jetties to access the inner harbor.  The channel is extremely narrow with a strong current that will either help or hinder your entrance to the harbor.  See local tidal charts to coordinate with your trip.

Inside The Harbor...

Once inside the jetties you will find that the narrow channel is well marked with red and green buoys.  The channel is dredged every few years and can accommodate large vessels.  These channel markers are privately maintained from April through November

To access the anchorage you will have to follow the channel deep into the anchorage.  There is a large sandbar along the western side of the channel.  The sandbar begins approximately half a mile inside the entrance. Click here for an Arial image of the sandbar.  You will not be able to pass over this sandbar.  At the northern point of the sandbar the depth is only a few inches at low tide.  In order to access the anchorage area you will need to pass the red "22" marker prior to turning into the western section of the harbor. 

Hazards inside the Harbor...

There are three major areas on concern inside or around Three Mile Harbor:  

• Rocks off Hog Creek Point:  See Above for more information.  Also see the waypoints list for exact location. Images of rocks: Image #1 & Image #2.
• Sandbar along western side of interior channel:  See Above
• Rocks along eastern shoreline inside Three Mile Harbor:   There are several rock clusters just outside the channel inside the harbor.  As long as your vessel remains well within the channel, you should not have any problems. Click for Image.

Important Waypoints...

Buoy Number	Location	Chart Image	JPG Picture
#2 Red Nun: .West of Three Mile Harbor before Cedar Point.	41° 03.350' N 072° 13.986' W
#1 Green Nun:  West of Three Mile Harbor before Cedar Point.	41° 03.333' N 072° 09.889' W
HAZARD: Lionhead Rock off Hog Creek Point.	41° 03.333' N 072° 09.889' W
Red & White Bell: .6 NM from entrance to Three Mile Harbor.	41° 02.651' N 072° 11.306' W
#2 Red Nun: At the entrance to Three Mile Harbor	41° 02.272' N 072° 11.346' W
#1 Green Buoy:  At entrance to Three Mile Harbor.	41° 02.286' N 072° 11.289' W
Green Tower: Tower at entrance to channel at end of the Jetty.	41° 02.093' N 072° 11.266' W
HAZARD: Sandbar separating inside channel and anchorage in Three Mile Harbor. Sandbar is just short of one mile long.	41° 01.496' N 072° 10.963' W
For more waypoints nearby see Shelter Island or Sag Harbor.