The alps were a big part of roman geography, it protected them from enemies, and was a trade route or other places, but that's really it, you can't really live up there. It was located at the very top of the boot, it is called a book because it looks like one.
The tiber river is probably the most important geographic location because it gave then protection, routed for boats, fish, water, and a way to get to the ocean quicker than normal. it is located near the capital
The roman capital is on one of these hills, this gives them protection and an advantage when fighting in wars, also, if they are standing of the hills, they can see farther.
Lastly... The peninsula, it is shaped like a high heel boot, it protects them from 3 sides, and then the mountains protect them on the last, a really conveniant place to live, very protective and safe.