Herndon Festival attendees enjoy connecting with businesses who participate in our Business Expo. Get started today to promote your business to over 60,000 patrons who will attend the annual Herndon Festival! The Herndon Festival Business Expo is held during the day on Saturday, June 3 and Sunday, June 4 at Northwest Federal Credit Union, 200 Spring Street. This is a unique opportunity and only thirty expo spaces are available. Fees vary by day or weekend, with a discount for Town of Herndon businesses. There is a discount for early bird registration.