Cruising/Navigating the GIWW in 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.


Found along the shores of the Mississippi Intracoastal Waterway

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.

Entrances, Inlets, and Passes

There are approximately (5) Entrances, Inlets, or Passes between the Gulf of Mexico and Mississippi’s Gulf Coast between Dauphine Island in the east and Cat Island in the west. All provide access to the sheltered inland waters of Mississipppi Sound as well as access to the Gulf Intracoastal Waterway.

While many of these are only suitable for shallow draft vessels and/or local knowledge, some can be considered navigable for most vessels. We have listed them below along with useful information on each to aid you in deciding if you wish to use a particular inlet.

Open Down Arrow GIWW - Mississippi Entrances, Inlets, and Passes
Pascagoula to Bay St. Louis

Horn Island Pass

Horn Island Pass is located 26.5 NM west of the entrance to Mobile Bay, AL. and is the only deep draft entrance into Pascagoula, MS. It lies between Petit Bois Island to the east and Horn Island to the west and allows access to Mississippi Sound, the Gulf Intracoastal Waterway, and Pascagoula.

The approach to Horn Island Pass is marked by a buoy (RW "HI" Mo (A)) at (30°08’30"N / 88°34’40"W); lying 1 NM SSW of the entrance channel.

Petit Bois Island and Horn Island are poor radar targets when approaching land from the Gulf of Mexico. Caution should be exercised when making landfall at night and during times of poor visibility. Vessels should approach Horn Island Pass and Pascagoula Harbor through the prescribed Safety Fairways.

Horn Island Pass has a dredged entrance channel; it is deep with a mid-channel controlling depth of 40+ feet and well-marked with lighted buoys and ranges that lead across the bar and into Mississippi Sound. The channel divides about 4 miles above the pass into channels leading north towards Bayou Casotte and northwest to the Port of Pascagoula. The entrance channel intersects with the Gulf Intracoastal Waterway 2.4 NM above the pass at MM "104.2 EHL" near buoys (G "29" Q G) and R "30" Q R).

Cautions – The Coast Guard advises vessels exercise particular caution where the channel intersects the Intracoastal Waterway, above the west end of Petit Bois Island near Lighted Buoys "29" and "30." Situations resulting in collisions and groundings are reported here by both shallow and deep-draft vessels. The Coast Guard has requested vessels make a SECURITE call on VHF-FM channel 13 prior to crossing the Intracoastal Waterway, particularly during periods of restricted visibility.

Dangers – Spoil areas are found along the sides of the dredged channels leading to Bayou Casotte and Pascagoula, MS.

Tides and Currents – In Horn Island Pass, the tidal range is about 1.4 feet and the tidal current is reported to flood north and ebb south averaging 1.2 knots at strength. It is reported that strong east winds and seas create strong currents along the shore.

Dog Keys Pass

Found 12.3 NM WNW of the entrance to Horn Island Pass and lying between Horn Island to the east and Ship Island to the west. It provides access to the GIWW and Biloxi, MS.

The approach and the beginning of the entrance channel is marked by a buoy (G "1" Fl G 4s at 30°12’56"N / 88°47’27"W). The Gulf Intracoastal Waterway intersects at MM "87.6 EHL" approximately 2.7 NM above the pass.

The natural channel of Dog Keys Pass has a depth of about 13 feet over the bar with slightly deeper water inside the pass. It is marked by lighted and unlighted buoys.

Dangers – The pass is surrounded by shoals and the entrance often breaks in moderate to heavy weather. Local knowledge is highly recommended.

Tides and Currents – Tidal range at Dog Island Pass is about 1.6 feet.

Little Dog Keys Pass

Little Dog Keys Pass, about 2.3 NM west of Dog Keys Pass, is used by sport fishermen and some commercial fishing craft. In July 1972, depths of 14 feet or more were reported available in the pass, and it was often used in preference to Dog Keys Pass. It is unmarked with shoals on both side of the pass. Numerous unmarked submerged pipes and obstructions are in the vicinity of the pass. Local knowledge is strongly recommended when using this pass. An unmarked wreck covered 11 feet was reported in Little Dog Keys Pass in about (30°14’10"N / 88°49’51"'W). The GIWW can be intersected 2.6 NM above at MM "3.5 EHL."

Ship Island Pass

Ship Island Pass lies immediately west of Ship Island, about 42 NM west of Mobile Bay Entrance in AL and 80 NM NNE of the entrance to Southwest Pass, LA. It is the principal deep draft entrance to the Gulf Intracoastal Waterway and Gulfport, MS.

The approach is marked by buoy (RW "GP" Mo (A) at 30°07’10"N / 88°52’40"W) equipped with an AIS transponder. Vessels should approach Ship Island Pass and Gulfport through the prescribed Safety Fairways.

Prominent is Ship Island Light (Fl 6s 82ft 6M at 30°12’45"N / 88°57’59"W) shown from the western end of Ship Island.

Ship Island Pass is well-marked by lighted buoys, and lighted ranges. It intersects the Gulf Intracoastal Waterway 5.0 miles above the entrance near (MM "73.0 EHL"). Gulfport Ship Channel then continues another 5 miles through Mississippi Sound to Gulfport Harbor Basin. Federal project depths are 38 feet for Ship Island Bar Channel, 36 feet for Gulfport Ship Channel, and 32 to 36 feet for the Anchorage Basin.

Dangers – Ship Island was cut into two parts by Hurricane Camille in 1969. The water between the existing parts is shoal with depths of 2 to 5 feet and much of it has not been surveyed. The shoal off the W end of Ship Island at West Point is moving west and is unmarked. Mariners should use caution if passing between the shoal and the edge of Gulfport entrance channel.

Tides and Currents – The diurnal range of tide is about 1.7 feet, but the tides are greatly affected by the winds. NE to S winds raise the level of the water, and SW to N winds lower the level. A continued norther makes a current on Ship Island Bar of as much as 3 knots. Current velocities up to 1.5 knots have been measured in Ship Island Pass during normal weather.

Cat Island Channel / South Pass

Cat Island Channel approximately 79.8 NM NNE of the entrance to Southwest Pass, LA lies between the southwestern tip of Cat Island and the eastern tip of Isle au Pitre. Cat Island Channel leads directly into South Pass, providing access to the western portion of Mississippi Sound, the GIWW, Bay St. Louis, and Pass Christian, MS.

The approach is marked by buoy (RW "A" at 30°10’47"N / 89°07’25"W) which marks the entrance to the channel.

The marked channel has a least depth of about 12 feet and is used primarily by local vessels. It is marked by unlighted fairway buoys ("B" through "F") and a couple of red nuns. Cat Island Channel and South Pass requires careful navigation in good weather conditions. It intersects the GICW near (MM "54.5 EHL") about 10.8 NM above the entrance.

Dangers – Cat Island Channel and South Pass are bordered by unmarked shoals covered 3 to 6 feet and a dangerous wreck was reported 0.3 mile NE of "Cat Island Channel West Buoy 2"; in about (30°11’22"N / 89°14’19"W) .

Tides and Currents – The range of tide is about 1.7 feet, but the tides are greatly affected by the winds. Current velocities up to 1.25 knots have been measured in the channel during normal weather.

Pass Marianne Notes:

Pass Marianne located 3.0 NM west of West Point on Cat Island. The mariner should use extra caution in this area between (MM "55.0 EHL") and (MM "65.0 EHL") of the Gulf Intracoastal Waterway. The area is subject to shoaling and frequent change.

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