The Yonko are the four most powerful pirates in the One Piece world and their influence is immense as well. In the New World, they rule like Kings and they have several powerful allies, as well as numerous territories under their control. A pirate cannot become a Yonko just by being strong. Other factors, such as how much territory and support they have also are very important factors.
Every Yonko in the series has offered their protection to some country for different reasons at some point and, given that many countries cannot afford to pay the Heavenly Tribute, they take protection from the Yonko instead. Some other countries are simply taken over by them. While every Yonko has some territories to their name, not all of them have the same number.
7 Buggy
Buggy is one of the newest members of the Four Emperors and he joined this group after the fall of Big Mom and Kaido in Wano. He received a bounty of 3.189 billion berries, which is nothing short of staggering. While Buggy isn't all that powerful, he does have powerful underlings such as Crocodile and Mihawk. At the same time, he has multiple allies, thanks to his role as the head of Buggy's Delivery.
All his allies from different countries of the world are likely under him at this point.
What's more, Buggy has also put up bounties on the heads of the Marines, which has only led to support growing for him. While fans do not know exactly how many territories he has under his name, his allies are many and that should be a decent indicator that he has quite a few countries that he protects.
6 Kaido
Kaido served as a Yonko for a very long time. Known as the Strongest Creature in the World, Kaido especially enslaved the people of Wano and ruled there with an iron fist for over 20 years. In the Wano Country arc, Kaido was finally defeated. Wano, one of the strongest countries in the entire world of One Piece that even the Navy was afraid of, was under him, which just goes to show how significant a threat Kaido was.
Furthermore, Kaido has several islands across the New World that belonged to him. This was confirmed to the fans shortly before the timeskip when X Drake met Scotch in combat on a winter island. Sadly, fans do not know much about the number of places that Kaido had under him. Now that he has fallen, it is likely that fans will never get an answer to that.
5 Luffy
Luffy recently became a Yonko after defeating Kaido – taking his place among the Emperor group. He received a bounty of 3 billion berries, which is nothing short of impressive. Luffy has already started to establish himself as a powerful Yonko. As mentioned earlier, strength isn't the only thing required to become one of the Four Emperors. A pirate must also have an incredibly powerful group of pirates under them and, at the same time several territories to their name.
Luffy has the Straw Hat Grand Fleet, which comprises of at least 5,640 powerful pirates. At the same time, several great countries, such as Wano, and even Fishman Island, are under his protection. There are many other countries that Luffy has saved or been to that will declare for him soon, such as Amazon Lily, Arabasta, and possibly even Dressrosa, among others.
4 Blackbeard
Blackbeard became a Yonko during the two-year timeskip of One Piece. He took the position of Whitebeard and aims for even greater things as the story progresses. Blackbeard is known to have the second-highest bounty among the Emperors right now at 3.996 billion berries. At the same time, he has many powerful allies who have pledged their sword to him and many countries under his flag as well.
It was made known that after the death of Whitebeard, Blackbeard started taking over the territories that the former had under him.
This means that the vast majority of Whitebeard's territories are currently controlled by Blackbeard himself. He is also the ruler of the Pirate Island at this point. Everything that he has accomplished so far has made him a fearsome figure in the One Piece world. Undoubtedly, Blackbeard deserves his recognition as one of the world's strongest pirates.
3 Shanks
Shanks has been a Yonko for 6 years now and, currently, he has the highest bounty of any member of the Four Emperors at 4.0489 billion berries. The Red-Haired Emperor is tremendously powerful and a glimpse of this was given to the fans during his short-lived battle against Eustass Kid, which he ended with a single swing of his sword.
Shanks also has many powerful countries under his flag. Fans saw Bartolomeo burn down his flag at one of his territories. Furthermore, the War Land Elbaf, known to be home to the strongest race in the entire world, is under Shanks' protection. There are also several other territories that Shanks has under his name and, unsurprisingly, he does not demand anything from the places that he protects. Shanks considers all of them to be his friends and, for his friends, he's willing to go to any lengths, as evident from the very beginning of the story. Shanks will only come into play more as the Final Saga of One Piece progresses.
2 Big Mom
Charlotte Linlin, also known as Big Mom, is one of the former Yonko and a pirate worth slightly over 4.3 billion berries. As a pirate, Big Mom is known to have the greatest intelligence network that can't be matched by any other member of the Four Emperors. At the same time, she also appears to have a vast number of territories under her protection.
Fishman Island, which currently is protected by the Straw Hat Pirates, belonged to none other than Big Mom until recently. At the same time, her home country, Totto Land, is composed of 34 different islands, each ruled by a different Minister. Furthermore, Big Mom was seen raiding several countries nearby and all of them were utterly defeated, which means they might now be under her protection as well. Big Mom's territory is massive and far more complex than any other Yonko seen in the series.
1 Whitebeard
Whitebeard is one of the most beloved characters in One Piece and at the same time, he was also the strongest man when he was alive. The legendary pirate captain was on a different level when compared to his fellow Yonko compatriots. He was equal to the late Pirate King, Gol D. Roger, and a phenomenon that only a few good stand next to.
Whitebeard also sailed the seas for a very long time and, during this time, he saved a lot of countries from utter destruction by putting them under his protection. After his death, fans saw the New World descend into a state of utter chaos, which implies that Whitebeard had numerous territories under him. Furthermore, it was also implied that Blackbeard started taking over his territories rapidly as he entered the New World. Surely, among the Emperors, Whitebeard had the most number of territories to protect.