Mississippi’s Coastal
Entrances, Inlets, & Passes

Whether you are making use of the Gulf Intracoastal Waterway (GIWW) or sailing coastwise along Mississippi’s Coast, there are a few Entrances, Inlets, or Passes between the deep waters of the Gulf of Mexico and the inland waters of Mississippi. From Petit Bois Island west to Bay St. Louis, there were 5 at last count in January 2020. All providing access to the sheltered inland waters of Mississippi Sound and providing 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.

Entrances, Inlets, and Passes

Entrances, Inlets, and Passes

There are literally hundreds of entrances, inlets, and passes between the Gulf of Mexico and the inside waters of Louisiana. Many only suitable for shallow draft vessels or local knowledge, but some can be considered navigable by most vessels. We are going to list only those that are important to accessing the Gulf Intracoastal waterway or that can be considered navigable for most vessels.

Open Down Arrow GIWW - Louisiana Entrances, Inlets, and Passes
The Rigolets to New Orleans

Chef Menteur Pass

Chef Menteur Pass, located 10.3 NM southwest of Rigolets Inlet. Provides access to the GIWW and Lake Pontchartrain.

The approach and entrance channel is marked by a lighted beacon (Fl R 4s 17ft 5M "2"). The approach is surrounded by shoals, but 6 feet can be carried with careful navigation and 5 feet can be carried over the shoals at most times.

Inside the pass, depths increase to 30+ feet mid-channel until reaching the Gulf Intracoastal Waterway. The pass is unmarked, but reportedly has good water nearly bank to bank.

Chef Menteur Pass intersects the GIWW 2.1 NM above the entrance marker at (MM "22.9 EHL") near lighted beacon (Fl R 2.5s 17ft 4M "4").

Cautions – A new Gulf Intracoastal Waterway alignment channel crosses Chef Menteur Pass 1 mile SSE of the original Intracoastal Waterway crossing, but reports are of shoaling to 3 feet. Caution is advised.

Southwest Pass

Southwest Pass, the westernmost of the passes for the Mississippi River and the only one capable of deep draft vessels. Besides the Mississippi River, the majority of the mid-west is accessible through this pass. From New Orleans, LA to the head of navigation in Minneapolis, MN.

The approach to Southwest Pass is marked by buoy (RW "SW" Mo (A) located at 28°52’39"N / 89°25’55"W), approximately 1.75 NM south of the entrance. Lighted buoys and ranges mark the approach.

Prominent on the approach is Southwest Pass Entrance Light (Fl 10s 122ft 12M at 28°54’21"N / 89°25’43"W) RACON equipped showing the Morse code equivalent of the letter "K" or (–·–).

The entrance has jetties on both sides with a range leading in. The channel through to the intersection with the Gulf Intracoastal Waterway and well above New Orleans is deep (45+ feet) with good water available bank to bank with few exceptions. It is well-marked by lighted buoys and lighted beacons.

Tides and Currents – The current, so far as is known, can be depended upon to set nearly straight out from between the jetties, but cross currents can be present due to winds and seas. Tidal range at the entrance is typically about 1 foot.

Intersection with the Gulf Intracoastal Waterway happens at a number of locations off the Mississippi River depending upon your direction of travel.

Algiers Navigation Canal Inlet

The Algiers Navigation Canal is located at MM "88.2 AHP": (97.8 NM above the Southwest Pass Entrance). It allows access to the GIWW when westbound. The canal has good water bank to bank and is crossed by (3) bridges, (1) fixed and (2) lift bridges. All bridges offer 100 feet of clearance.

The canal entrance is on the south side of the Mississippi River and intersects the GIWW at MM ("6.5 WHL" near lighted beacon (Fl (2+1) R 6s 20ft 3M).

Inner Harbor Navigation Canal

The Inner Harbor Navigation Canal entrance is on the north side of the Mississippi River and provides access to and is part of the Gulf Intracoastal Waterway. This inlet is for vessels eastbound on the GIWW.

The intersection with the GIWW takes place at MM "92.5": AHP located approximately 101.6 NM above the Southwest Pass Entrance or about 80.5 NM Above Head of Passes (AHP). The inlet is marked by (2) lighted beacons: Fl G 2.5s 30ft 4M "1" on the west side and Q R 40ft 4M "2" on the east side.

Cautions – When turning in from the Mississippi River, be aware of a stump awash (at 9.9 feet water level) about 10 feet out from the east bank.

Tides and Currents – Tides in this area are almost non-existent except at the lowest of Mississippi River Water Stages. Tidal currents likewise do not exist other than the currents due to the outflow of the river.

Harvey Canal

Located approximately 2.9 miles above the Crescent City Connector Bridges, it is marked by a traffic light to control entry. This canal is actually part of the Gulf Intracoastal Waterway with the Harvey Lock being MM "0.0." It marks the split between mileages measured East of Harvey Lock (EHL) and West of Harvey Lock (WHL).

The canal has good water bank to bank and is crossed by both bascule and fixed bridges with a minimum vertical clearance of 95 feet.

Open Down Arrow GIWW - Louisiana Entrances, Inlets, and Passes
New Orleans to Cameron

Cat Island Pass

Cat Island Pass is well marked with lighted buoys, daybeacons, and ranges. It has a controlling depth of 13’, but minimum depths of 10’ have been noted.

Cat Island Pass intersects the Houma Navigation Canal 1.5 miles above the entrance. From the Houma Navigation Canal, the least depth reported was 10’ to its intersection with the GIWW at Houma, LA at (MM “59.6 WHL”), 36.8 miles above Cat Island Pass.

Atchafalaya Bay Inlet

Atchafalaya Bay Inlet is located between Point au Fer Island to the west and Eugene Island to the west. It is deep (20’) and well-marked by buoys and daybeacons. Point au Fer Light is the most prominent navigation aid in the area.

From the entrance, a dredged channel leads to the Lower Atchafalaya River and on to its intersection with the Gulf Intracoastal Waterway at (MM “98.2 WHL”) 26.9 miles above the entrance.

Calcasieu Pass

Calcasieu Pass is a deep-draft channel leading to Lake Charles, LA. It is deep with a minimum controlling depth of 33’ and is well-marked with buoys, daybeacons and ranges. The entrance is protected by jetties. The approach channel is marked by a fairway buoy RW “CC” showing a Mo (A) white light.

Calcasieu Pass intersects the GICW at (MM “241.5 WHL”) 24 miles above the entrance.

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