Louisiana’s section of the Gulf Intracoastal Waterway (GIWW/GICW) begins near the mouth of the Pearl River, MS near (MM "41.0 EHL") at 30°15.042’ N / 88°23.666’ W in Lake Borgne.
From Lake Borgne, this section of the GIWW runs generally in a westerly direction for 307.0 miles ending at 30°03.2’ N / 93°43.2’ W (MM "266.0 WHL") on the Sabine River at the Texas state line.
Louisiana’s GICW is marked with your standard Aids to Navigation which also display yellow triangles or yellow squares. When westbound along Louisiana’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 along this route in the vicinity of the Mississippi River, Lower Atchafalaya River, Vermilion River, and Calcasieu River where the GIWW intersects or coincides with the channels marked by the Lateral Buoyage System.
NOAA chart coverage of this portion of the GIWW beginning at (MM “41.0 EHL”) to (MM "266.0 WHL" is provided by charts #11367, #11365, #11355, #11350, #11348, and #11331. These charts can be viewed by clicking on the links below:
All distances along the Louisiana’s Gulf Intracoastal Waterway are given 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.
This portion of the GIWW between the Mississippi State line and the Texas State line is measured based on both decreasing and increasing mileage East and West of Harvey Lock from (MM "41.0 EHL") to (MM "266.0 WHL").
The Federal project depth for the Louisiana portion of the Gulf Intracoastal Waterway provides for a minimum 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.
All operating bridges in Louisiana guard VHF Channel 13. The locks found within the state guard either channel 14 or channel 13.
The U.S. Coast Guard advises all vessels to exercise caution in any area where the GIWW intersects major shipping channels. A “Security Call” on VHF channel 13 is requested prior to crossing any shipping channels, especially during periods of restricted visibility.
Bridges, Locks, & Overhead Power Lines
This list is believed to be accurate as of
If any errors or omissions are noted, please e-mail us at
with any corrections or recommendations.
The draw shall open on signal if at least 24 hours notice is given.
Forked Island Bridge
W. Creole Highway/Gibbstown Bridge
Grand Lake Pontoon Bridge
Opens on Demand
Black Bayou Pontoon Bridge
Opens on Demand
Closed Mon-Fri 0600 to 0800 and 1400-1600.
Ellender Lift Bridge
Opens on Demand (4 Hour notice required).
The above tables can be downloaded for your personal and private use. They list the bridges, their schedules, and restrictions in statute miles, nautical miles, and kilometers along Louisianna’s segment of the Intracoastal Waterway from the Pearl River in Louisiana west to the Texas State line.
Operates within the operating times of the Florida Avenue, Claibourne, and St. Claude operating bridges.
Bayou Boeuf Lock
Overhead Power Lines
Quite a few overhead cables cross Louisiana’s Gulf Intracoastal Waterway. Numerous cable crossings with a minimum authorized clearance noted at 90’ are located between (MM "34.0 WHL") and (MM "135.0 WHL"). (1) overhead cable at (MM "219.9 WHL") has been reported to have a clearance of only 82’.
Caution - Many of the overhead cables over the waterway carry high voltage, and an extra margin of safety should be allowed when the weather is threatening.
Tidal ranges are fairly small along Louisiana’s coast. Under normal conditions the mean range of tide averages between less than 0.5 foot at Chef Menteur Pass to about 1.0 foot across the remainder of the state to the Texas State line.
Louisiana experiences (2) types of tides; from the Mississippi state line west to Vermilion Bay the type of tide experienced is commonly refered to as a "Diurnal Tide" - exhibiting (1) high tide and (1) low tide each day. West of Vermilion Bay to the Texas State Line, a "Mixed Tide" gradually takes over having (2) unequal high and low tides each day.
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.