Typically exits are often one mile apart, but if you are in a big metro city they are much closer with A, B, C D and other letters assigned to the exit number… Also, the exit numbers starts from 1 as you enter a new state and goes up by 1 for every mile until you cross the state.

Are exits based on miles?

Exit Numbering - CA Numbered Exit Uniform System (Cal-NExUS)

Exits are numbered from south to north on north-south routes and west to east on east-west routes. Each exit number is determined by the number of miles it is from the beginning of the route.

Do all states have mile markers?

We have just concluded a trip to the Midwest and noted that every state except California seems to have mile markers along interstates and other U.S. highways. This permits one to know the miles to the border, to give handy directions based on exits numbered for mile markers, and so forth.