The Diamond Bar Center has a beautiful ballroom and multiple meeting rooms for your upcoming event. Our Grand View Ballroom can accommodate up to 438 people for a seated dinner or up to 822 for a seated presentation or lecture. Our four smaller meeting rooms are ideal for small meetings or gatherings. Each room offers ample natural light. Our Sycamore room combines the flexibility of indoor and outdoor space, utilizing the beautifully landscaped adjacent patio.