Republican Robert L. Ehrlich Jr. leads Democrat Kathleen Kennedy Townsend 46 percent to 43 percent in the race for Maryland governor, according to a poll for Washington television station WRC-NBC4 released yesterday.

The poll is the first to show Ehrlich with a lead in the tightening contest, although it has a margin of error of 4 percentage points, meaning the race remains a statistical tie, as other recent polls have suggested. It was conducted by Mason-Dixon Polling & Research Inc., which surveyed 625 likely voters statewide.

Brad Coker, a director with Mason-Dixon, said Townsend's support was slipping in Montgomery and Prince George's counties, the state's two most populous counties, where she previously had scored well.