The largest & wildest Halloween street party in the United States. The West Hollywood Halloween Costume Carnaval spans over one mile of historic Route 66 in the heart of West Hollywood. Santa Monica Boulevard is closed between La Cienega and Doheny Boulevards to host over 350,000 attendees. Many will be wearing some of the most fun and unique Halloween costumes anywhere. In addition, four stages will feature non-stop talent, dancing and costume contests. The highlight of the evening will be the crowning of the new celebrity Honorary Mayor.