Maryland Route 22

Maryland Route 22 (MD 22) is a state highway in the U.S. state of Maryland. The state highway runs 12.91 miles (20.78 km) from U.S. Route 1 Business (US 1 Business) and MD 924 in Bel Air east to an entrance to Aberdeen Proving Ground in Aberdeen. MD 22 is the main connection between the county seat of Bel Air and Aberdeen, which is the largest city in Harford County. The state highway also provides the primary route between Interstate 95 (I-95) and Aberdeen Proving Ground; that section of MD 22 is a part of the National Highway System.

MD 22 was one of the original state roads marked for improvement in 1909 and one of the original state-numbered highways in 1927. The highway was constructed between Bel Air and Aberdeen in the early 1910s. Another section of highway between Aberdeen and Havre de Grace, the Post Road, was also built in the early 1910s. The Post Road became part of US 40 in 1927 but was designated as an extension of MD 22 after US 40 was relocated in the early 1930s. MD 22 was reconstructed from Bel Air to Aberdeen in the 1950s. MD 22's present course east of I-95 was built in the late 1960s; the old section of MD 22 through Aberdeen became MD 132.