Route information is arranged in groups of 20, for a total of 50 pages. Interstate, US, and state highways have their own sub-section, with basic information included for all on the state route pages. It's in a table format, as shown in the sample below:
County
Town
Town.
Road Name(s) ...
A green sidebar indicates the route number is posted by the SHA. Along the side are the counties the route passes through, and towns along the way. A town is included on the list if it appears on the Maryland official highway map and is within one mile of the route.
Associated Secret-Obscure Routes: 811
878 989
Signed routes are bold, secret are normal, and decommissioned routes are italic.
In this example, Route 811 is signed, 878 is secret, and 989 is history.
At right is a mileage log for all signed routes. The mileage begins at 0 at the routes southern or western terminus. Mileages appear in red. In black is the road or junction involved. Only county lines and junctions with other state routes are shown. For limited access highways, all roads with an interchange are shown, with name instead of number. State roads 'passed over' by a limited access highway are not shown in the mileage table for that particular road. The exit number, when applicable, is shown in blue. If the highway crossing a route has an exit number, that number is shown in purple. For example, our mythical MD 997's Exit 3 is with I-97, and from I-97's viewpoint, 997 is Exit 19. (perhaps a future I-97 spur ;)
These mileages come from the SHA Highway Location Reference (HLR) for 1997. The HLR is also the source for all the total mileages at the top of the center section.
County
Town
Town
Road Name (-[year decommissioned])
A brown sidebar indicates the route number is no longer assigned to a particular road. The route may have been fully dropped from state maintenance, or made part of another route. It may or may not have ever been signed.
County
Town
Town
Road Name...
A blue sidebar indicates the route number is not posted, making this a 'secret' route. It's not really a secret, as SHA and some commercial maps will show them. There's no way of telling them from other signed routes; although they're mostly confined to the higher numbers above 600 or so, there are many signed routes among the high numbers.