Biggest Eagle Ever
The biggest eagle ever recorded were the Haast's Eagles (Harpagornis moorei). The extinct eagle has a body measuring (4.7 ft) long. Across the wings, it measures 10 feet. The eagle weighed in at 33 lbs.
Other Large Eagles
The Australian Wedge Tailed Eagle has the longest wingspan. They have been estimated at 230cm to 250cm. Some species have been estimated to have 300cm wingspans. The heaviest living eagle is Steller's Sea Eagle. It weighs 15-20 lbs.
In terms of physical dimensions, the biggest is the Philippine Eagle. On the average it is 95-112 cm long and over a meter high. The Philippine Eagle also has the biggest wing surface area. It also has the biggest claws and longest legs. But if body mass relative to the size is considered, the biggest eagle ever would be the Harpy Eagle.
Location
The eagle can be found on all continents with the exception of Antarctica. There are sixty known species. A bird of prey, the eagle can thrive in different environments. Most of them are found in Asia, Europe and Africa.
Serpent Eagles
These are found in Africa and Asia. There are 12 species known. Their diet consists of reptiles and snakes. These eagles are smaller compared to others.
Bald Eagles 
This is one of only two eagle species in the North American continent. Almost extinct in the early 20th century, efforts were made to conserve it. The Bald Eagle was taken off the endangered animals list in 2007.
Hawk-Eagles
In spite of the name, these are not hybrid hawks / eagles. The name was used because they were once thought to be hawks. Most of the Hawk-eagles are found in South and Central America. Some species are also found in Africa and Asia. Their most distinguishing trait is the head crest. The Hawk Eagle family includes the Martial Eagle and Crowned Eagle.
True Eagles
These include several eagles like the Tawny Eagle, Spotted Eagle and Golden Eagle. These are found in Africa, the Indian subcontinent and Asia. The Hasst’s Eagles belonged to this group.
Sea Eagles
The Sea Eagle family includes Steller’s Sea Eagle and the Bald Eagle. They are among the oldest species in the world. Recent estimates say they have existed for over 20 million years.
With so many variants, determining the biggest eagle ever today is not as easy as it seems. To determine what the largest is, you have to decide what definition to apply as shown above.
