sentences:  MD 21 was resurfaced with bituminous concrete in 1975.The highway's westernmost , measured from the high-water mark of the Chesapeake Bay, was transferred from state to county maintenance through an August 16, 1990, road transfer agreement.The western terminus of MD 21 was moved again, this time to MD 445's northern terminus, when the portion of MD 21 between MD 445 and Tolchester Beach was transferred from state to county maintenance through a June 1, 1993, road transfer agreement.