Green’s Dictionary of Slang

dingnation! excl.

a euph. for damnation! excl.

[US]W.T. Thompson Major Jones’s Courtship (1872) 189: April Fool, dingnation!
[US]Anderson Intelligencer (SC) 7 Feb. 1/5: Where in the wide world did you learn to say [...] dingnation and blame my skin and dad burn it all?
Manning Times (Clarendon Co, SC) 17 July 4/5: Damn is a more convenient and expressive word than dogon or dingnation.