The Democratic and Republican parties hold their caucuses at the same time this year starting at 7 p.m. CST on Feb. 1 at spots in all of Iowa's 99 counties. Caucuses are held in each of the state's 1,681 precincts, but the number of meeting sites is smaller because some precincts share buildings. Democrats will meet at about 1,100 spots and Republicans will gather at nearly 900. Voters from some small precincts meet in homes, but most join in schools, veterans' halls and other large venues.

The parties hold their caucuses simultaneously, but they operate differently.