Maritime Highways

[hobsini2]

I came across something last week that I did not know existed. Marine Highways. These are for ships to use navigable waters. And the all have designations. A lot of the water designations coincide with a land designation.
Here is the map:
https://geodata.bts.gov/datasets/2f8f522f630e4cf5b754ab9e4b64e37e_0/explore?location=36.219778%2C-95.283523%2C4.70

Here is a quick rundown of the routes for which waterways:
M-2 - Puerto Rico coastline loop
M-3 - Kaskaskia River - Chester IL to Fayetteville IL
M-5 - Pacific Ocean and Puget Sound - San Diego CA to Bellingham WA
M-5 AK - Alaska coastline
M-10 - Gulf of Mexico/America - Brownsville TX to Port Manatee FL
M-29 - Missouri River - Kansas City MO to Sioux City IA
M-35 - Upper Mississippi River - Grafton IL to Minneapolis MN
M-40 - Arkansas, Verdigris and White Rivers - Catoosa OK to Napoleon AR
M-49 - Atchafalaya River and J. Bennett Johnson Waterway - Morgan City LA to Shreveport LA
M-55 - Lower Mississippi, Illinois, and Des Plaines Rivers and Ship Channel - New Orleans LA to Chicago IL
M-65 - Mobile Bay, Black Warrior River and Tombigbee Waterway - Mobile AL to Birmingham AL and Cairo IL
M-64 - Hampton Roads, Chesapeake Bay and James River - Norfolk VA to Richmond VA
M-70 - Missouri, Mississippi and Ohio Rivers - Kansas City MO to Pittsburgh PA
M-71/M-77 - Lake Erie - Cleveland OH to Detroit MI
M-75 - Detroit River and Lake Erie - Toledo OH to Detroit MI
M-84 - Columbia, Williamette and Snake Rivers - Astoria OR to Lewiston ID
M-87 - Hudson River and Erie Canal - New York NY to Albany NY
M-90 - The Great Lakes and St Lawrence Seaway - Duluth MN and Chicago IL to St Lawrence Seaway and Albany NY
M-95 - Atlantic Ocean - Miami FL to Portland ME
M-146 - Galveston Bay, Buffalo Bayou and Houston Ship Channel - Galveston TX to Houston TX
M-295 - East River, Long Island Sound, Block Island Sound - New York NY to Block Island RI
M-495 - Anacostia, Potomac and Occoquan Rivers - Chesapeake Bay to Washington DC
M-580 - San Francisco Bay, Sacramento and San Joaquin Rivers - San Francisco CA to Sacramento CA and Stockton CA
M-A1 - Matanuska and Susitna Rivers - Palmer AK to Cook Inlet AK
M-AS1 - American Samoa coastline loop
M-GNM1 - Guam and Northern Mariana Islands coastline loop
M-H1 - Hawaii coastline loop
M-V1 - US Virgin Islands coastline loop

I did notice quite a few other navigable bodies of water not on the list.
That list will be posted later.

[freebrickproductions]

I think M-65 has signage for it as you cross it on US 72 in Burnsville, MS, ain't seen any anywhere else though, at least off the top of my head.

[formulanone]

Mississippi likes to sign them...

I-22/US 78 at the Tombigbee Waterway:



US 49 out of Mississippi; though the little bridge tag looks like we're technically in Arkansas.

[Road Hog]

Arkansas and Oklahoma probably don't sign M-40 because it's close to I-40.

The White River should be M-140 anyways.

[Henry]

Arkansas and Oklahoma probably don't sign M-40 because it's close to I-40.

The White River should be M-140 anyways.

I, too, have noticed that most of the M-numbers duplicate the Interstates that serve the same areas. So unoriginal of them, and why do they have to exist in the first place?

[TheCatalyst31]

Arkansas and Oklahoma probably don't sign M-40 because it's close to I-40.

The White River should be M-140 anyways.

I, too, have noticed that most of the M-numbers duplicate the Interstates that serve the same areas. So unoriginal of them, and why do they have to exist in the first place?

Then I assume the Kaskaskia River got its number from IL 3, because otherwise I'm not sure how such a short bit of navigable river got a single-digit number. Given the other waterways listed I'm a little surprised it's even in the system.

[TBKS1]

Arkansas and Oklahoma probably don't sign M-40 because it's close to I-40.

mic drop

[hobsini2]

Arkansas and Oklahoma probably don't sign M-40 because it's close to I-40.

The White River should be M-140 anyways.

I, too, have noticed that most of the M-numbers duplicate the Interstates that serve the same areas. So unoriginal of them, and why do they have to exist in the first place?

Then I assume the Kaskaskia River got its number from IL 3, because otherwise I'm not sure how such a short bit of navigable river got a single-digit number. Given the other waterways listed I'm a little surprised it's even in the system.

That is correct. Apparently, the Kaskaskia River is deep enough for barge traffic.

[hobsini2]

The other bodies of water that are not listed that one would think could be on the list are:

Alabama River - Mobile AL to Montgomery AL
Apalachicola and Chattahoochee River - Apalachicola FL to Columbus GA
Calcasieu River - Cameron LA to Lake Charles LA
Chesapeake & Delaware Canal - Crystal Beach MD to Delaware City DE
Connecticut River - Old Saybrook CT to Greenfield MA
Cooper, Congaree, and Broad Rivers - Charleston SC to Lockhart SC
Delaware Bay and Delaware River - Lewes DE to Easton PA
Housatonic River - Stratford CT to Shelton CT
Kennebec River - Popham Beach ME to Augusta ME
Merrimack River - Newburyport MA to Nashua NH
Narragansett Bay - Narragansett RI to Providence RI
Penobscot Bay and Penobscot River - Vinalhaven ME to Medway ME
Red River - Shreveport LA to Dennison TX
Sabine River - Port Arthur TX to Carthage TX
Savannah River - Tybee Island GA to Augusta GA
St Johns River - Palatka FL to Atlantic Beach FL
Susquehanna River - Havre de Grace MD to Harrisburg PA
Tennessee River - Florence AL to Chattanooga TN
Thames River - New London CT to Norwich CT

[TBKS1]

US 49 out of Mississippi; though the little bridge tag looks like we're technically in Arkansas.

shoutout to the Helena Bridge, here's the other side, it's also signed there too!

[GaryA]

Is this "highway system" used by anyone?  I mean, there's obviously lots of river shipping and pleasure boating, but does anyone use these highway numbers, or consider which waterways are and are not included in the system, when planning a trip?

Or is its main function just to try to educate the general public about how significant water traffic is to the economy?

[hobsini2]

Is this "highway system" used by anyone?  I mean, there's obviously lots of river shipping and pleasure boating, but does anyone use these highway numbers, or consider which waterways are and are not included in the system, when planning a trip?

Or is its main function just to try to educate the general public about how significant water traffic is to the economy?

Here's the government website giving you the "purpose".
https://www.maritime.dot.gov/grants/marine-highways/marine-highway#:~:text=The%20United%20States%20has%20a,that%20promote%20marine%20highway%20transportation.