The Second Punic War. Hannibal was ingenious at warfare, and pretty much every battle in the war was heavily influenced by geography. Cannae is a fine example.

This is a pretty broad subject, as geography has always been a fundamental factor in warfare. This ranges from the scale of grand strategy - eg. the strategic importance of Crete in the ancient world or the island status and naval trading system of Britain vs. Napoleon's continental system - to the specific geography of individual battles at specific sites on particular days - what would Agincourt have been like had it not rained so heavily in the days before or Towton if there had not been a snowstorm?

It seems to me there are two approaches you can take. The first is to take classic texts like Sun Tzu, Von Clausewitz, Goderian, Fuller, and look for the geography in them. The second is to take a specific country or conflict (or maybe a small number of similar/dissimilar cases).

Russia makes a good study, since its geography is much commented on. From Napoleon to Hitler, invaders have been able to make rapid progress across its great plains, but have fallen foul of the tremendous distances and the harsh conditions.

Even just referencing Sun Tzu's The Art of War, the concept of seeking higher ground before your enemy can has been pursued as a means of gaining advantage in battle.

This probably isn't your timeframe, but in the Cold War the pursuit of this "higher ground" is what drove much of the energy behind the establishment of orbiting earth satellites and putting men on the moon.

Thank you for all your recommendations!

The Dardanelles and subsequent Gallipoli campaign in the First World War is a perfect example - I wrote an article on it here. Just make sure you cite it if you do end up using it ;)

Geography and technology influence the types of soldiers, equipment and training, which influences tactics, which then utilize advantageous terrain. There's two levels that I see geography influencing warfare: The more obvious level is that hills, mountains and rivers change where armies march and can march. The second, further removed from warfare, defines what armies are composed of.

The Iliad discusses battles in terms of chariots, spears, swords and the occasional bow, while Hannibal crossed the Alps with Elephants. Not only did geography influence the tactical specifics, but geographic distance, rough terrain, the difficulty of supplying an army abroad, all influence the composition of that army even before it starts fighting. In rough terrain, and chariot is less useful. If distance from home resources are great, and you can't pillage what you need from your enemy, you have to spread your army out, or starve.

There's a lot of tactical suggestions here already. If you're looking a level above (which I don't use to mean 'better') that, you could look at various continental invasions of England and the effect of the English Channel. (Trafalgar, 1805, was a failed attempt by France and Spain to gain local superiority in the English channel, in order to facilitate an invasion. If it wasn't for that natural barrier, naval warfare wouldn't have been nearly as important. For instance, there were no huge naval conflicts between France and continental powers in teh Napoleonic wars) Or the geographic distance the Atlantic and Pacific Oceans had on the United States' delayed entries into WWI and WWII, and the strong isolationist movements. Or Roman incursions into German forests, and how a Roman Legion's equipment and training designed for an open field, didn't work so well in a restrictive forest. Or American Civil war naval innovation: designed for brown water coastal warfare, and mostly unsuited for any long distance travel and ocean waves. The geographic distance between the United States and Europe was a significant barrier in WWII to transporting weapons; Nazi U-Boats grew specifically out of the requirement to limit the amount of shipping, and the entire WW2 submarine warfare was possible because of the Atlantic Ocean. The Cold War, and proximity between NATO and USSR lines in Europe dictated the technology used: Tanks were a dominant ground weapon due to their mobility in wide open spaces, and specific weapons (like the A-10 or AH-64, were designed specifically to defeat the overarching threat.

Hi there, I would recommend the Ottomans against the Russians, defense of Istanbul and access of the Mediterranean, the Sinai Desert as a natural barrier between the Ottomans and the British in WW1 and the geography of European colonisers in the 15th-19th centuries. Island grabbing and coastline controlling.

Firstly my main interest is the clash of the Ottoman Empire with European powers in the early 20th century and there are several interesting battles and ongoing conflicts fought by the Ottomans. For example the desire of the Russian Empire to claim Istanbul for access to the Mediterranean for the Black Sea Fleet. Another aspect of geography you could look at is the Sinai desert and the campaign the Ottomans/Germans tried to run against the British in the early days of WW1. The long desert hike made it easy for the British to see the Ottomans coming and defend against them. The Sinai acted as a natural barrier between the two powers, allowing the British to keep and control the Egyptian territory from the Ottomans.

Secondly, I would say look at the geography of European powers claiming colonies around the world. Portugal in particular had colonies on the periphery of landmasses, an easy of transport for their navy just starting out in the colonial campaigns. Just look at the British/French acquisition of all those Islands and strategically important outlets that are still held onto i.e Britain in Gibraltar which still ruffles up Spain and the Brits in Cyprus, a key choke point for Suez, the Black Sea and access for the Air Force into the Middle East. Even at the conference of Berlin, Britain managed to come out on top because of their already established coastline colonies down the African East coast, France gaining West Africa because of their launchpad position north of Africa. All gained through European colonialism. All geographically important.

Good luck with your paper.

I just wanted to put a note here in case any mods come along and think about deleting this question.

This sounds a lot like a "throughout history" question, which would be against the rules. However I think the primary questions are actually about methodology and historiography, ie. "how do I approach this very broad topic?" and "what are the key texts or other sources that can help me?"