Gulf Intracoastal Waterway - Mississippi

Petit Bois Island, MS to Campbell Island, MS

The Mississippi portion of the Gulf Intracoastal Waterway (GICW) has its beginning near the eastern point of Petit Bois Island, MS near (MM "111.1 EHL") at 30°15.042’ N / 88°23.666’ W in Mississippi Sound.

This section of the GICW runs generally in a westerly direction for 70.1 miles ending at 30°09.4’ N / 89°30.5’ W (MM "41.0 EHL") in Lake Borgne, MS, 2.0 miles SE from the mouth of the Pearl River at the Louisiana State line.



Mississippi’s GICW is marked with your standard Aids to Navigation which also display yellow triangles or yellow squares. When westbound along Mississippi’s Gulf Intracoastal Waterway, marks displaying yellow triangles should be kept on your starboard hand and those marked with yellow squares should be kept to port.

While typically the yellow triangles will be found on red markers and yellow squares are found on green markers, caution should be exercised in Mississippi Sound where the GICW intersects or coincides with the Pascagoula Main Ship Channel, the Biloxi Bay Entrance Channel, and the Gulfport Sound Channel, marked by the Lateral Buoyage System.


NOAA chart coverage of this portion of the GICW beginning at mile marker "111.1 EHL" to mile marker "41.0 EHL" is provided by charts #11374, #11372, and #11367. These charts can be viewed by clicking on the links below:

Chart #11374 - Dauphin Island to Dog Keys Pass
Chart #11372 - Dog Keys Pass to Waveland
Chart #11367 - Waveland to Catahoula Bay

Distances and Mileages

All distances along the Mississippi's Gulf Intracoastal Waterway are in statute miles unless otherwise noted. Statute miles are used in order to conform to the distances shown on the small craft charts typically used along this route.

The Mississippi portion of the GICW, between the Alabama State line and the Louisiana State line, is measured based on decreasing mileage (East of Harvey Lock - EHL) from (MM “111.1 EHL”) to (MM "41.0 EHL".)


The Federal project depth for this section of the Gulf Intracoastal Waterway provides for a channel depth of 12 feet. Even though every effort is made to maintain the project depth, the actual controlling depths in the channels may vary due to shoaling reducing the available water depth until maintenance dredging can be accomplished.


Bridges, Locks, & Overhead Power Lines





Overhead Power Lines


Note: This is the only state on the entire Intracoastal Waterway System (AICW or GICW) where the waterway is not crossed by either bridges or overhead power Lines.


Tidal ranges are small along Mississippi’s coast line. Under normal conditions the mean range of tide averages around 1.5’ at Pascagoula and decreases to about 0.75’ in the vicinity of Biloxi and Gulfport. The tidal range then increases back to about 1.1’ in the vicinity of the Pearl River and the Louisiana State line.

The type of tide experienced in this area is commonly referred to as a "Diurnal Tide" - exhibiting (1) high tide and (1) low tide each day.

Inlets & Passes

There are approximately (6) Entrances, Inlets, or Passes between the Gulf of Mexico and this section of Mississippi’s Gulf Intracoastal Waterway. Many of these are only suitable for the smallest of vessels with shallow draft, but some can be considered navigable by most vessels.

Horn Island Pass

Horn Island Pass is the entrance for Pascagoula, MS and intersects the GICW 2.9 miles above the entrance near (MM "104.0 EHL"). This is a deep and well-marked channel with buoys and range lights. The approach is marked by Horn Island Buoy “HI” Mo (A).

Ship Island Pass

Ship Island Pass leads to Gulfport, MS; it is well-marked by lighted and unlighted buoys, and lighted ranges. It intersects the GICW 5.0 miles above the entrance near (MM "73.0 EHL"). Gulfport Ship Channel continues another 5 miles through Mississippi Sound to Gulfport Harbor Basin. Project depths are in excess of 30 feet to the Basin.

Cat Island Channel

Cat Island Channel lies between Cat Island to the northeast and Isle au Pitre to the southwest. This (not so well) marked channel has a least depth of about 12 feet and is used primarily by local vessels. It is marked by unlighted fairway buoys and a couple of red nuns and requires careful navigation in good weather conditions. It intersects the GICW near (MM "54.0 EHL") about 12.4 miles above the entrance.


The mariner should use a little extra caution in the "Pass Marianne" area between (MM “65.0 EHL”) and (MM “55.0 EHL”0. This area is subject to frequent change.

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