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Forest Service Roads

How are Forest Service Roads Numbered?

If you’ve ever driven through a U.S. National Forest and saw a small sign with a series of numbers and letters posted at the start of a road, you’ve found yourself a Forest Service road.

How are Forest Service roads in U.S. National Forests numbered? Each National Forest in the U.S. assigns a short number and letter combination to each Forest Service road. The road numbers are unique for each state and a few different naming conventions are employed.

So how exactly does that work? Read on and we’ll go into greater details on how this great system works.

How the U.S. Forest Service Numbers Their Roads

Before we get started, it’s important to know that there is no universal naming convention employed by all the National Forests. Many National Forests employ similar conventions, but each is ultimately free to choose their own method, so your mileage may vary.

How to Find the Forest Service Roads for your National Forest

As this process is specific to each unique National Forest, the first step is to go to the website for the National Forest you’re interested in exploring. Simply enough, go to the U.S. Forest Service website and find your National Forest in the dropdown box, then click the ‘Go’ button.

Once you’ve found the website for your National Forest, find the navigation pane and go to the ‘Maps & Publications’ part of the menu. This should be available for each National Forest, as it doesn’t appear that the navigation menu changes in any way. However, what you see once you’ve navigated to the Maps & Publications section is unique.

What we’re looking for now is something called the ‘Motor Vehicle Use Map,’ otherwise referred to as the MVUM. Every National Forest should have the MVUM somewhere on this page, it’s just that the different forests format this page differently. Once you find the MVUM, you should look for links to PDF maps of the Forest Service roads. Most National Forests will have several different maps that showcase different sections of the forest, but some may have only a single map.

screenshot of the motor vehicle use map section for us forest service website in missouri
Here is the Motor Vehicle Use Map section for the Shawnee National Forest

Each MVUM should have a key that explains what the different stylings mean. There also will be tables that provide more information about roads that have restricted use, whether that be restrictions based on vehicle type or seasonality.

Difference in Numbering Methods for Different National Forests

Most National Forests name their Forest Service roads with a three to five digit combination of numbers and letters. Each National Forest is free to name their roads with whatever conventions they like, so understand that there isn’t a singular method applied universally.

However, know that most of the National Forests use numbers to designate the main roads, and then letters are used as modifiers that are most commonly used with smaller branches of roads. A hypothetical example: a National Forest has a main road with a number of 1234, with a branched road of 1234A. More on that later.

Quick Note: as the Forest Service maintains tens of thousands of roads throughout the vast network of National Forests in the United States, you can expect that some numbers will be reused. It’s important to note that the numbers for all Forest Service roads are unique to that state, so keep that in mind.

Roads Branching Off a Main Road

A common theme running through many National Forests is that a main Forest Service road may have smaller roads branching off of it, and those smaller roads are often named in a way to easily highlight that relationship.

For example, the Shawnee National Forest in southern Illinois names their Forest Service roads with a 3-digit number, and then appends a letter to the end if that road branches off a main road. Below you can see a screenshot of on of the Motor Vehicle Use Maps, which shows the main road (750) and the attached sub road (750D):

up close screenshot of roads in motor vehicle use map with road numbers visible

Not just limited to one level of branching, you can see in the below screenshot that there can be branched roads off of other branched roads. This creates a situation where an already branched road (Forest Service road 307C) can have two roads branching off of it, with names that indicate that relationship (roads 307CA and 307CB).

motor vehicle use map with branched roads visible

While this all may be a little confusing at first, I promise you you’ll appreciate the value the first time you get a little lost exploring a National Forest. In this case, if I got turned around while driving on FS 307CA it would be easy for me to get back to FS 307C, and then I could reach FS 307, which appears to be a regular road.

This is all very helpful from a navigation standpoint, as being able to quickly navigate from the remote trunk roads back to the main road keeps people from getting lost. Anyone who’s tried to navigate a dense forest without a map will appreciate that.

How Forest Service Roads are Marked in the Forest

As helpful as it is to explore the National Forests with the maps, most of us would prefer to spend much more time actually in the forest. So, how does the Forest Service mark the different Forest Service roads in the actual forest?

From my experience, the Forest Service roads are posted with a sign at the spot where the road bisects another road. For example, the Forest Service road 743A would have a marker posted at the spot indicated in the below screenshot:

road intersection point for motor vehicle use map

This would likely be the only marker on that road, as the road is a dead end that doesn’t encounter any other road.

It’s also helpful to know that most of the time Forest Service roads have very limited signs posted on them, so I wouldn’t expect to see signs posted anywhere else on this road. Remember, you’re deep in a National Forest, not on the interstate. Don’t expect to be constantly reminded which road you’re on, so it is your responsibility to pay attention and notice the signs you’re given.

Concluding Thoughts

I hope this article was helpful for you and you picked up a few things that you didn’t know before.

If you need more ideas about making the most out of our National Forests then check these articles out:

By Drew Meulemans

I've long admired forests and devote much energy to learning about them and exploring. I enjoy sharing what I learn and wish to inspire others to do the same.