Mason-Dixon is a game of alternate history. It posits a North America where the CSA defeated the USA in the Civil War and has further conflicts in following years. The game has three scenarios: 1917, 1940, and 1995. The map represents most of the CSA and a large portion of the USA and has 538 counters (some for each of the three secnarios). Hexes are 33 miles across, and counters generally represent 20-30,000 men or up to 400 combat vehicles. Aircraft counters represent varying numbers of planes, and naval counters are individual capital ships. Player turns are 10 days in the two early scenarios, and 2 days in the 1995 one.