Mainlinie

The Mainlinie (German for "Main-line") refers to the historical and political boundary between northern and southern Germany along the River Main.

The line delimitates the spheres of influence of Austria and Prussia in the German Confederation during the 19th century.

The seat of the German Confederation, Frankfurt am Main, sat upon the line.

Eventually, the Main line became the southern boundary of the North German Confederation.

[1] Today, the Main line is viewed as the boundary between northern and southern Germany.