, is a major east-west highway connecting
U.S. Route 29 in
Ellicott City and
Maryland Route 177 /Mountain Road in
Pasadena . Route 100 also connects to
Interstate 95 ,
U.S. Route 1 , the
Baltimore-Washington Parkway , and
Interstate 97 . The highway connects
Howard County, Maryland , to the west with
Anne Arundel County, Maryland , and the
Chesapeake Bay to the east. Route 100 also provides access to the
Baltimore-Washington International Airport and the
Arundel Mills Shopping Mall .
Route 100 began in the
1970s as two separate roads, both retaining the Route 100 designation. The first was known as the Mountain Road Extension, stretching between
Governor Ritchie Highway and the old
Maryland Route 3 , now
Interstate 97 . The second was built as a short spur between the newly constructed
Interstate 95 and
U.S. Route 1 in
Elkridge, Maryland . The eastern section, originally known as the Mountain Road Bypass, was constructed east of Ritchie Highway in the late 1970s. Route 100 was completed west of I-97 to I-95, thereby connecting the two roads, in
1994 , but was not completed in its entirety to U.S. 29 until
1998 .
The eastern section of Route 100 in
Anne Arundel County is known as the Paul T. Pitcher Memorial Highway.
