Lake District vs Lakeland

Lake District and Lakeland both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lake District	Yes	No	No	No
Lakeland	Yes	No	No	No

As nouns, Lake District and Lakeland are synonyms defined as:

Lake District and Lakeland: a popular tourist area in northwestern England including England's largest lake and highest mountain

Lake District (noun)	Lakeland (noun)
a popular tourist area in northwestern England including England's largest lake and highest mountain	a popular tourist area in northwestern England including England's largest lake and highest mountain