Wikipedia
Interior lines is a strategy of warfare that is based on the concept that lines of movement, communication, and supply within an area are shorter than those on the outside or exist on the inside exclusively. As the area held by a defensive force shrinks, the advantages increase.
Using the strategy of interior lines, a surrounded force can more easily supply, communicate, and move its forces around, and it can mount a series of quick attacks on the forces encircling it.
Usage examples of "interior lines".
The German people, operating on interior lines, on a grid of railroads brilliantly designed by Moltke for the swift shuttling of armies, with an industrial plant planned and built for war, all but beat a coalition that included nearly the whole world.
Hoffmann now proposed a maneuver by which the Eighth Army, taking advantage of its interior lines and the use of railways, could so dispose itself as to meet the threat of both Russian armies and, if things developed as he thought they would, be in a position to throw all its weight against one of them.
In the first place, it assigned the two columns advancing from Canada rather long lines of march over bad roads through hostile, unfamiliar country where supplies would be hard to obtain, and it gave the Americans an opportunity to unite their forces and meet and defeat the columns one at a timethe classic advantage of interior lines.
We're going to fight that sort of battle, and our only real advantages are interior lines and position.