Green’s Dictionary of Slang

Yankee Doodle n.

an American, spec. a New-Englander.

1812		T. Moore in Examiner 8 Mar. 157: I might have withheld these political noodles / From knocking their heads against hot Yankee Doodles.
1815		H.H. Brackenridge Modern Chivalry (1937) Pt II Vol. IV 648: All are called Yankees by the British; but New-England men are distinguished; and called Yankee Doodles.
1837		W. Dunlap Memoirs of a Water Drinker 14: He was a Yankee I believe [...] King of the Yankee-doodles!
1851		Manchester Spy (NH) 1 Nov. n.p.: For ’twas an honor to his race / What Yankee Doodle done.
1869		Sportsman (London) 4 Oct. 2/1: Notes on News [...] The American-Irish bosh [...] has Yankee-doodle-Wearing-of-the-Green twang about it.
1904		Sydney Sportsman (Surry Hills, NSW) 16 Mar. 2/4: Oh, just the marvel of the age / Is Uncle Yankee Doodle!
1912		Truth (Wellington) 22 June 1/7: The Yankeedoodler [...] concluded their intelligence was of so low a standard.
1914		A. Brazil Leader of the Lower School 74: ‘Wish you could make some [fudge] here, Yankee Doodle!’.

In derivatives

Yankeedoodledom (n.)

the world of New Englanders.

1884

Daily Morn. Astorian (Astoria, OR) 18 Mar. 1/1: The brass mounted minions of Yankeedoodledom made us a social call.