sentences:  However, there have been numerous changes to county borders since that time, most recently when portions of the city of Takoma Park that had previously been part of Prince George's County were absorbed into Montgomery County in 1997.Outside of Baltimore (which is an independent city) the county is the default unit of local government.Under Maryland law, counties exercise powers reserved in most other states at the municipal or state levels, so there is little incentive for a community to incorporate.