Yes, most states require that you indicate your party affiliation in order to vote in primary elections. (There are some exceptions.) When you register to vote using our online voter services, you will be automatically informed of your state requirements.
Most Secretary of State websites provide further information about which parties allow unaffiliated voters to participate in their primary election. You can find your state’s website by going to the page. Select your state, and on the following page select you voting location and “State Lookup Tools” to find a link for your state’s elections website.
You do not need to declare your party affiliation if you only plan to vote in the November general election and not in the primary election.