The "Official Mileage Guide for the State of Texas" has been in existence since 1974 when the then Comptroller certified and adopted the guide for use by state employees for reimbursement of travel. It received the designation "Official" because it was and still is the only mileage guide that always provides a listing that is the shortest distance between two points (computed using Texas Dept. of Transportation district maps).

 The Official Mileage Guide for the State of Texas (OMGST) is a privately produced point-to-point mileage guide based on center-stripe surveyed distances, and is updated annually.

 The OMGST is the only mileage guide available in which all mileages are determined as the shortest distance between points, including farm-to-market roads.

The 2000 Official Mileage Guide for the State of Texas includes both a Windows-based disk containing a point-and-click mileage database and a map set. The OMGST map set is a detailed set of maps listing over 1150 key points, and can be used to determine the distance between any two points in the state. The map set also includes insets of every major metropolitan area in Texas, so the origin and destination points employees and suppliers travel to most frequently can be precisely located. This easy-to-use map set is specifically designed with the needs of the work-related traveler, accountant and auditor in mind, and each sectional map overlaps by fifty miles for ease of use.