[10][11] Maryland Route 204 was the designation for Poplar Street and Ray Road from the Takoma Park town limit east to MD 212 in Chillum in northern Prince George's County.

[15] Maryland Route 206 was the designation for 38th Street from US 1 Alternate in Cottage City north to US 1 in Brentwood in northern Prince George's County.

[19] The highway was paved as a concrete road by Prince George's County with state aid from Bladensburg Road to what is now Rhode Island Avenue in Brentwood, then southwest along Rhode Island Avenue to the District of Columbia boundary in Mount Rainier between 1916 and 1919.

[26] Maryland Route 209 was the designation for Ager Road and Hamilton Street from MD 212 in Chillum east to Hyattsville in northern Prince George's County.

[27] The highway was paved as a 14-foot-wide (4.3 m) concrete road by Prince George's County with state aid by 1915.

[23] Maryland Route 211 was the designation for Sargent Road from the District of Columbia boundary north to MD 212 within Chillum in northern Prince George's County.

[16] The highway was paved as a concrete road by Prince George's County with state aid between 1916 and 1919.

[7] The portion of the highway closest to Wayside was built as a 9-foot-wide (2.7 m) gravel road by Charles County with state aid by 1915.

[21] MD 229 served as the terminus of a ferry between Morgantown and Colonial Beach, Virginia, beginning in or shortly before 1933.

[22] The ferry was discontinued between 1940 and 1946 following completion of the Potomac River Bridge between Newburg and Dahlgren, Virginia, in 1940.

[37] The first section of the highway was built from MD 5 west about halfway to Millers Wharf Road in 1926 and 1927.

[11] Maryland Route 268 was the designation for the Port Deposit Road, which ran 11.68 miles (18.80 km) from US 40 (now MD 7) in Perryville north to US 1 at Conowingo in western Cecil County.

[MD 269 3] The highway from Port Deposit to Liberty Grove was constructed starting in 1916 and was mostly complete by 1920.

[MD 280 10] The portion of the highway from the north town limit of Elkton to the Baltimore & Ohio Railroad (now CSX's Philadelphia Subdivision) crossing at Singerly was constructed as a 14-foot-wide (4.3 m) macadam road in 1911.

The highway from the south town limit of Elkton at Big Elk Creek toward Chesapeake City was started in 1911 and completed as a 14-foot-wide (4.3 m) macadam road in 1914.

[MD 280 16] The highway from Fair Hill to the Pennsylvania state line was constructed as a concrete road between 1930 and 1933.

[14] Maryland Route 321 was the designation for Main Street in Elkridge with two sections: from MD 477 to Brumbaugh St, and from Railroad Ave to US 1.

Maryland Route 325 was the designation for Wade Avenue from Spring Grove State Hospital north to MD 144 in Catonsville.

[20][21][30] The state highway was extended south to Cambridge when the first Choptank River Bridge opened in December 1935.

[4][22] MD 344 was replaced by US 213 in 1939 when the U.S. Highway was rerouted via Cambridge between Vienna and Easton instead of via Hurlock and Preston.

[40] Maryland Route 345 was the designation for Table Rock Road from US 50 near Redhouse south approximately 1 mile (1.6 km) along Backbone Mountain.

[28] In addition, a section of concrete road was constructed along Main Street in Fruitland to connect the highway with Camden Avenue, which became part of US 13 (now US 13 Business) in 1927.

[14] Maryland Route 351 was the designation for the 4.24-mile-long (6.82 km) portion of Ballenger Creek Pike from the beginning of state maintenance near Tuscarora Creek in Adamstown, which was 6.77 miles (10.90 km) north of the named road's southern terminus in Point of Rocks, north to MD 180 and I-70 in Frederick.

[57] Maryland Route 359 was the designation for Boone Road from MD 380 near Crisfield south to a point north of the hamlet of Byrdtown in southern Somerset County.

[59] The highway was constructed as a gravel road from the Quaker Burying Ground, which is adjacent to the MD 255–MD 468 intersection, east to Galesville in 1929 and 1930.

[1] Maryland Route 394 was the designation for Market Street through Snow Hill in central Worcester County.

[61] In 1983, US 220 was removed from the streets of Cumberland and instead used the Cumberland Thruway through the city; the U.S. Highway replaced MD 395 from the eastern end of the freeway west to MD 807, where the highway turned north onto Bedford Road toward Bedford, Pennsylvania.

[38] MD 144 replaced US 220 on Naves Cross Road when US 220 was moved to its present alignment north of Cumberland in 2000.

[62] Maryland Route 398 was the designation for Greencastle Pike from US 11 in Williamsport north to MD 58 at Cearfoss in central Washington County.

[22] The portion of Greencastle Pike from Cearfoss to the Pennsylvania state line remained a county highway.