The information presented here is designed to help you locate rest areas along Interstate highways. Understanding how the information is presented, and learning the difference between a mile marker and exit number, will aid you in using this site.

Mile Markers
Mile markers, or mileposts as they are also known, are the vertical green signs on the edge of highways placed at one-mile intervals. Mile marker numbering begins at the most southerly or westerly point in a state. For example, if you enter Colorado from New Mexico, mile markers will increase as you travel north through Colorado. Likewise if you were to enter Colorado from Utah, mile markers would increase as you travel east through Colorado. California is the only state that does not use mile markers. Instead they use a Post Mile system with numbering beginning and ending at county lines.

Exit Numbers
Interstate exit numbers are determined by one of two methods. The first, and most widely used, is based on the mile marker system. Using this method, the first exit number on an Interstate as you travel south to north or west to east is determined by its distance from the state line. For example, if an exit is located between mile markers 4 and 5, it is numbered as Exit 4. The next exit, if located at mile marker 8.7, would be numbered as Exit 8. Thus you would know that you must travel approximately 4 miles to reach the next exit. Using this method of exit numbering helps to determine the location and distance to a desired exit.

The second method of numbering Interstate exits is the consecutive numbering system, which means Interstate exit numbers begin at the most southerly or westerly point and increase consecutively as you travel north or east. Using this method, the first exit on an Interstate as you travel south to north or west to east is Exit 1. Each exit thereafter increases consecutively as Exit 2, Exit 3 and so on. Few states use this method of numbering Interstate exits.

California's Numbering System
As mentioned above, California does not use mile markers nor does it indicate exits with a number. This is changing, however. In January of 2002, California began erecting signs displaying exit numbers based on the mile marker system. The exit numbers and mile marker numbers used on this web site are based on the proposed numbers that California has assigned.

Rest Area Charts
Rest area information is presented in a chart. Depending on your direction of travel, you'll either read up the chart or down the chart. If you are traveling north or east, read up the chart. If you are traveling south or west, read down the chart. See below for an explanation of each column heading.

Interstate
The Interstate number.

Exit(mm)
The exit or mile marker where the rest area is located. Mile markers are surrounded by parentheses.

Dir
The direction of travel served by the rest area. Abbreviations are as follows:

b - accessible to both directions of travel
sb - accessible to southbound travelers
nb - accessible to northbound travelers
eb - accessible to eastbound travelers
wb - accessible to westbound travelers

Locale
The name of a nearby city or town.

Type
The type of rest area including:

Rest Area
Welcome Center
Service Plaza
Turnout

Rest Area Amenities
Information about amenities available in each rest area (such as family restrooms or wireless Internet access) can be found in the Interstate Rest Area Guide ebook.

Please Note
Although efforts are made to ensure the accuracy of the information presented, Roundabout Publications shall have neither liability nor responsibility to any person or entity with respect to any loss or damage caused, or alleged to be caused, directly or indirectly by the information contained herein.