Depends on what you mean by "large". Rayquaza is the tallest legendary pokemon, being 23 feet (23'/7m) tall but is 455 pounds (455lbs./206.5kg).
Giratina, though, is large in both height and weight. It was originally supposed to be 22 feet and 8 inches (22'08"/6.9m) and weigh at 1433 pounds (1433lbs./650kg), but was altered to be 14 feet and 9 inches (14'09"/4.5m) and weigh at 1653.5 pounds (1653.5lbs./750kg).
Edit: I forgot to mention that Groudon could also be qualified as the "largest" legendary pokemon. Even though it is only 11 feet and 6 inches (11'06"/3.5m) tall, Groudon is the heaviest weighing at 2094.4 pounds (2094.4lbs./950kg). It is also the heaviest pokemon ever. Also, Giratina's original stats landed it 3rd for heaviest pokemon after Groudon and Dialga (1505.8lbs/683kg) but its current stats make it 2nd place. Plus, Giratina would've original been the 5th tallest pokemon but is now the 10th tallest along with Kyogre.
Added bonus: Despite Rayquaza being the tallest legendary pokemon, it is only the 4th tallest pokemon. The tallest 3 pokemon are Wailord (47'07"/14.5m), Steelix (30'02"/9.2m), and Onix (28'10"/8.8m).
It is a rare pokemon, but it is not a legendary pokemon
Unknown is not a legendary Pokemon but it is considered rare. Legendary Pokemon are one of a kinds.
No, snover is not a Legendary Pokemon
No, Blastoise is not a legendary pokemon.
Is sawk a legendary pokemon??
It is a rare pokemon, but it is not a legendary pokemon
Unknown is not a legendary Pokemon but it is considered rare. Legendary Pokemon are one of a kinds.
no lileep is not a legendary pokemon but it is an ancient pokemon
Groudon, Kyogre, and Rayquaza. Groudon is the fire legendary pokemon, Kyogre is the water legendary pokemon, and Rayquaza is the air legendary pokemon.
Arcanine is not a legendary Pokemon because legendary Pokemon can't be breeded and arcanine can.
The legendary is palkia
No, snover is not a Legendary Pokemon
No, Blastoise is not a legendary pokemon.
Noivern is not a Legendary Pokemon.
Is sawk a legendary pokemon??
Azelf is a legendary Pokemon.
It is absolutely impossible to get Legendary Pokemon eggs.