Maryland Route 100 (MD 100) is a major east–west highway connecting U.S. Route 29 (US 29) in Ellicott City (just north of Columbia) and MD 177 (Mountain Road) in Pasadena. MD 100 also connects to Interstate 95 (I-95), US 1, the Baltimore-Washington Parkway (MD 295), and I-97. The highway connects Howard County to the west with Anne Arundel County and the Chesapeake Bay to the east.