DUMFRIES, Va. (AP) — Northern Virginia’s first licensed gambling operation is opening up to the general public.

Rosie’s Gaming Emporium in Dumfries in southern Prince William County is opening Friday after a soft opening of several days.

The gambling hall has 150 machines that function like slot machines, but the payoffs are actually tied to the results from an archive of old horse races.

Rosie’s outlets have been popular in Richmond and three other locations in Virginia. State law dedicates a small portion of the machines’ proceeds to supporting purses at Virginia’s only horse track, Colonial Downs in New Kent County.

While Rosie’s is the only gambling hall licensed in the wealthy northern Virginia market, it will face competition from full-fledged casinos bordering the state in Maryland and West Virginia.