The other three cities are Des Moines, Iowa, Fayetteville, Arkansas, and Memphis, Tennessee.
A full distance Ironman consists of a 2.4-mile swim a 112-mile bicycle ride and a 26.2-mile run.
Ironman officials say communities can see a $10 million impact from hosting a competition.
Representatives plan to visit all four cities again and pick a host in mid-June.
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