Every city has one-of-a-kind sites for memorable group events—landmark museums, stylish nightclubs, mansions, penthouse suites, theaters. An online tool for researching and booking these singular venues, Eventup, is celebrating its one-year anniversary and its expansion into the Washington, D.C., market.

When Eventup launched last February, it listed venues only in Los Angeles, but the company has steadily branched out. In addition to 1,200 L.A. sites, the database now covers seven cities: New York (close to 1,000 venues), San Francisco (600+), Chicago (400+), Miami (150), Boston (150), Atlanta (200), and Washington, D.C. (200). If the company sticks to its aggressive expansion schedule for the first half of 2013, it will add venues in Philadelphia in February; Houston and Dallas in March; Seattle, Phoenix, Baltimore, and San Antonio in April; Portland, Austin, Denver, and San Diegoin May; and Jacksonville, Minneapolis, St. Louis, and Salt Lake City in June.

Using Eventup, planners can search for a venue by zipcode or city (and neighborhoods within a city), budget, venue type (gallery, bar, banquet hall, residence, rooftop), group size, and event type. Users can also indicate whether they need access to audiovisual support, catering, or a full bar.

The results are eclectic. In a recent search for event spaces in Boston for a corporate group with 75 people, the database returned 50 venues including the familiar Wilbur Theater and the Spirit of Boston harbor cruise ship, along with lesser-known choices such as The University of Massachusetts Club, the Artists for Humanity Epicenter building, a funky loft in the Leather District, the Waterworks Museum, and the Underbar nightclub and lounge.

While some planners may just browse the Eventup site for inspiration, the system is set up to take users through the buying process, including creating an event profile, requesting quotes, scheduling visits, and booking the event. Eventup won’t disclose the exact number of events it has booked through the system but says it’s “in the hundreds.” The service is free to planners. Venues pay Eventup 15 percent of the cost of the venue rental (space only, not the catering, entertainment, or other costs) when a group books.