Arguably the largest feline of the domestic breeds, the Serval cat a wild cat tamed to behave like a domestic cat. Small enough for that purpose but they are special and require a host of special requirements and care. photograph © Kathrin Stucki of A1 Savannahs
People searching for the largest feline are searching for the largest cat as the word "feline" means belonging to the Felinae family of animals and these include both wild and domestic cats. We need to separate the wild from the domestic as wild cats are generally much bigger than domestic cats, but not always. Some wild cats are very small and some domestic cats are bigger than the some wild cats.
There is a page on the Pictures of Cats website that deals with the largest domestic cat breed. It also deals with the smallest domestic cat breeds as a consequence and makes some comparisons in size between domestic cats and wild cats that are similar in size. There is a complication here as one or two wild cats have been tamed to become domestic cats (Serval - see above and Safari). Also there are a number of wild cat hybrids, the first generation offspring of which are large and semi-wild producing an overlap between wild and domestic cat. The classic wild cat hybrids are the Bengal and Savannah but you can see them all; in fact all the domestic cat breeds illustrated by the best pictures anywhere on the Pictures of cats website.
Largest Domestic Cat Breed
A particularly large domestic cat breed is the F1 (first generation Savannah), probably the largest domestic cat breed (or largest feline of the domestic cat breeds) but not recognized by most of the cat associations:
F1 Savannah Cats
As for the largest wild cats, two come to mind and there are pages on this website on both. One is a man mad wild cat to wild cat hybrid, the Liger:
What do Liger Eat? - this post features the worlds biggest cat or largest feline at the date of this post. If it has changed or I am wrong, please leave a comment.
The other wild cat that is the biggest wild cat breed is the Tiger:
Worlds Largest Cat (breed)
I think that more or less covers all the angles if someone is looking for the largest feline.
Largest Feline to Home page