River Coordinates & Distances | Mississippi River Source to Sea 2023

Someone who wasn't familiar with the Mississippi River might assume that there would be a map somewhere with a set of river miles starting at the headwaters and counting down to zero where it reaches the Gulf of Mexico. Sadly the reality is a little more complicated.

There are actually two major river mile coordinate systems for the Mississippi River. 

Upper River Miles (URM) go from URM 1,342 at the Lake Itasca headwaters to URM 0 at the confluence with the Ohio River at Cairo. 

At that point the river switches over to Lower River Miles (LRM) starting with LRM 954 and count down to LRM 0 at Head of Passes down past Venice. 

If you take the New Orleans route the actual point where you reach salt water at the end of south pass is 13 miles past Head of Passes or LRM -13.

If you take the popular alternative down the Atchafalaya then we couldn’t find an official set of coordinates but mapping the route we found to be most commonly used by paddlers exiting via Hog Bayou is 141 miles from Old River Lock. So a person grasping for order might say Old River Lock is ARM141 and Burns Point is ARM0.

So now that you know the river miles exist how would you figure out what you are at while your actually on the river? 

Initially you have it easy as the start of the river is covered by 10 Minnesota DNR maps you can find here or download using the Avenza phone app which will show you your location on the PDF. River miles are listed for all major points of interest making it really easy to keep track of everything. 

Unfortunately these only cover as far as Hastings and we never found an ideal replacement.

Lower down the river there are physical nav beacons on the shore which sometimes have the mile on them. But be aware that the Mississippi River has a tendency to change over time and at least one Army Corp of Engineers document I found only guarantees the nav buoy numbers were accurate to 15 miles. They had a note that they generally do their best but don’t treat anything like gospel.

There are additional Army Corp of Engineers charts for the river but these were so zoomed it as to be less than ideal for our uses.

At times we saw houses or other locations on the river labeled with the river mile but this was inconsistent. 

I wanted to keep it simple and have mile markers on my phone GPS app so with a huge amount of help from our friend Dennis (aka the awesome guy who makes those lovely maps at the start of each of our videos) we came up with the following. Take it, use it, hell get the army corp of engineers to republish it for all we care. The universe could use the extra bit of sanity.

Upper River Miles (URM): Headwaters URM 1,342 to Cairo URM 0

Lower River Miles (LRM): Cairo LRM 954 to Head of Passes LRM 0

Actual end of the New Orleans route LRM -13

Atchafalaya Route: Old River Lock A 141 to Burns Point A 0

For a more logical way to divide up the river see my writeup on the river by sections.

Note that this means your total distance paddled from the headwaters to the gulf is somewhere in the vicinity of 2,309 miles if exiting past NOLA or 2,133 exiting via Atchafalaya. Also anyone actually doing the river has probably done a fair chunk extra along the way.