The next section of present-day MD 33 was constructed between Claiborne and the highway's present western terminus on Tilghman Island as MD 451. The sections from Claiborne to a point between Wittman and Sherman and on Tilghman Island were completed around 1930. The gap between Knapps Narrows and Sherman was filled in 1933. MD 451 was completed when a new single bascule drawbridge was completed over Knapps Narrows in 1934. MD 17 was extended from Claiborne across Eastern Bay along Romancoke Road to MD 404 in Matapeake on Kent Island in 1938. This section was added in response to the replacement of the Claiborne–Annapolis ferry route with a Claiborne–Romancoke route in 1938, with traffic following the new section of MD 17 to Matapeake to take a second ferry across the Chesapeake Bay to Annapolis. MD 17 switched numbers with MD 33, the highway connecting Brunswick and Wolfsville in Frederick County that is now MD 17 in 1940.