Per the Iowa Secretary of State’s website:
Caucus locations are set by the Democratic and Republican Parties. These locations may not be the same as your election polling place. To find your caucus location please visit the party’s website below:
Iowa Democratic Party: https://iwillvote.com/locate/
Republican Party of Iowa: https://www.iowagop.org/2020-caucus-locations
More on the Iowa Caucus and its history HERE.