cut out a part of your complex vector graph - make clip using Illustrator

If you have a very complex vector graph (map here, many lines), you want just a part of that complex graph. How can you do that, using Adobe Illustrator?

using clipping mask.

(1) you need select all elements of your map, and group them
(2) then, generate a path here red rectangle, which just indicate the rang you want

(3) select all (the map in group and the red rectangle) you have, then go to Object/clipping mask/Make

(4) see what you want

(5) using Artboard Tool to tuning the outlay of your graph