The Maryland highway system has several hundred former state highways. These highways were constructed, maintained, or funded by the Maryland State Roads Commission or Maryland State Highway Administration and assigned a unique or temporally unique number. Sometime after the highway was assigned, the highway was transferred to county or municipal maintenance and the number designation was removed from the particular stretch of road. In some cases, a highway was renumbered in whole or in part. This list contains all or most of the state-numbered highways between 400 and 499 that have existed since highways were first numbered in 1927 but are no longer part of the state highway system or are state highways of a different number. Most former state highways have not had their numbers reused. However, many state highway numbers were used for a former highway and are currently in use. Some numbers have been used three times. The former highways below whose numbers are used presently, those that were taken over in whole or in part by another highway, or have enough information to warrant a separate article contain links to those separate highway articles. Highway numbers that have two or more former uses are differentiated below by year ranges. This list does not include former Interstate or U.S. Highways, which are linked from their respective lists.

__NOTOC__

MD 400

Maryland Route 400 was the designation for Mount Wilson Lane, which ran from MD 140 west to the Western Maryland Railway (now CSX's Hanover Subdivision) and the former Mount Wilson Hospital Center near Garrison in western Baltimore County. The highway was paved as a concrete road in 1930. MD 400 was removed from the state highway system in 1991.

MD 401

Maryland Route 401 was the designation for Stringtown Road from MD 25 east to Yeoho Road near Butler in northern Baltimore County. The highway was constructed as a macadam road in two segments in 1932 and 1933. MD 401 was removed from the state highway system in 1987.

MD 403

Maryland Route 403 was the designation for what was then named Colesville Road, which ran from MD 500 in Hyattsville east to US 1 in Riverdale in northern Prince George's County. Colesville Road was constructed as a modern highway between 1940 and 1942. MD 403 was resurfaced in 1954, shortly before the highway was taken over by MD 410 when that highway's modern alignment through Hyattsville was completed in 1956.

MD 403 (1930)

Maryland Route 403 was the designation for a loop off of MD 155 west of MD 161 via Level Village Road. It was deleted in 1942. It appears on a 1937 map and a Maryland SRC operating budget.

MD 406

Maryland Route 406 was the designation for Rehobeth Road from MD 667 at Hudson Corner east to US 13 in West Pocomoke in southern Somerset County. The first section of MD 406 was completed east from what was then MD 413 in 1930. MD 406 was taken over by MD 667 when that highway's terminus was shifted from Westover to West Pocomoke in 1961.

MD 408

Maryland Route 408 was the designation for Edgewood Road from the Edgewood Arsenal (now part of Aberdeen Proving Ground) north to MD 7 in Edgewood in southern Harford County. The highway was built as a concrete road south from US 40 (now MD 7) in the community of Van Bibber south to the military installation in 1930. MD 408 was constructed with a width of but was proposed for widening to as early as 1934. The highway received an underpass of the Baltimore & Ohio Railroad (now CSX's Philadelphia Subdivision) and approaches to the grade separation in 1939. MD 24 assumed all of MD 408 when MD 24 was extended south from MD 7 to Aberdeen Proving Ground in 1952. Much of what had been MD 408 is now part of MD 755.

MD 409

Maryland Route 409 was the designation for Freeland Road from the Northern Central Railway at Freeland to east of I-83 at Maryland Line in far northern Baltimore County. The highway was constructed as a concrete road from Freeland to US 111 (now MD 45) in 1929 and 1930. MD 409 was extended east through the I-83 interchange after the freeway was built between Parkton and the Pennsylvania state line in 1958 and 1959. The highway was removed from the state highway system in 1991.

MD 411

Maryland Route 411 was the designation for Rhode Island Avenue from former MD 206 (now MD 208, which follows 38th Street) in Brentwood east to US 1 (now US 1 Alternate) in Hyattsville in northern Prince George's County. The portion of Rhode Island Avenue from the District of Columbia east to 38th Street was built as a concrete road as part of MD 206 between 1916 and 1919. The remainder of MD 206 along 38th Street to Cottage City is now part of MD 208. MD 411 was constructed as a concrete road in 1929 and 1930 from Brentwood to Hyattsville. By 1934, the highway was proposed to be expanded to because it carried an average of 19,105 vehicles per day. MD 411 was widened to from Brentwood to Hyattsville between 1938 and 1940. The MD 411 designation may have been extended west from 38th Street to the District boundary by 1939. Rhode Island Avenue also may have been part of US 1 Alternate and US 50 Alternate; US 1 and US 50 then entered the city along Bladensburg Road. The MD 411 designation was removed when US 1 was placed on Rhode Island Avenue from Washington, D.C., to Hyattsville by 1946; old US 1 along Baltimore Avenue and Bladensburg Road became US 1 Alternate.

MD 412

Maryland Route 412 was the designation for Riverdale Road from US 1 east to MD 201 in Riverdale. The highway was constructed as a concrete road in 1929 and 1930. At the Baltimore & Ohio Railroad, MD 412 used one-block portions of Rhode Island Avenue, Queensbury Road, and Lafayette Avenue to connect with the segments of Riverdale Road on either side of the tracks. However, by 1956, the highway used Queensbury Road west to US 1 in the 1950s before reverting to Riverdale Road around 1963. The highway was truncated on the east side of the railroad in 1978. MD 412 was removed from the state highway system in 1991.

MD 415

Maryland Route 415 was the designation for Scotland Beach Road from MD 5 east to the Chesapeake Bay shore near Scotland in far southern St. Mary's County. The highway was constructed as a gravel road in 1930. MD 415 was removed from the state highway system in 1956.

MD 416

Maryland Route 416 was the designation for Southern Maryland Boulevard from MD 2 in Sunderland north to MD 4 at Waysons Corner in northern Calvert County and southern Anne Arundel County. Southern Maryland Boulevard was constructed as an concrete road on a new alignment in 1929 and 1930. MD 416 was widened to along its whole length and resurfaced in 1948. The highway was relocated at Lyons Creek at the county line between 1953 and 1956. MD 416 was expanded to a divided highway from Waysons Corner to south of Lyons Creek in 1962 concurrent with the construction of MD 4's bypass of Upper Marlboro. In 1960, MD 416 was extended south from Sunderland on a long concurrency with MD 2 to the latter highway's terminus at Solomons. In 1965, MD 416 was replaced by MD 4 from Waysons Corner to Solomons; the portion of MD 4 east of Waysons Corner became MD 408.

MD 417

Maryland Route 417 was the designation for Springs Road from US 40 (now US 40 Alternate north to the Pennsylvania state line in Grantsville in northern Garrett County. The highway went under construction in 1930 and was completed as a concrete road by 1933. MD 417 was replaced by MD 669 to match the adjacent Pennsylvania Route 669 in 1963.

MD 419

Maryland Route 419 was the designation for a pair of highways near Dickerson in western Montgomery County. One highway followed Mount Ephraim Road from MD 28 at Dickerson north to near the intersection of Mount Ephraim Road and Sugarloaf Mountain Road. The other used Martinsburg Road from MD 28 south to where Martinsburg Road curves south near the Potomac River. Both segments of MD 419 were constructed in two sections. The northern MD 419 was constructed as a concrete road from MD 28 to north of Barnesville Road in 1929 and 1930. The highway was extended to its northern terminus in 1931 and 1932. The southern MD 419 was built as a concrete road from MD 28 to near Wasche Road in 1929 and 1930. The highway was extended as a macadam road to where Martinsburg Road bends south near the Potomac River in 1931 and 1932. Both segments of MD 419 were removed from the state highway system in 1959.

MD 420

Maryland Route 420 was the designation for Brink Road from Goshen Road east to MD 108 in Laytonsville and Sundown Road from MD 108 east to a spot east of Laytonsville in northern Montgomery County. The portion of the highway between MD 124 and MD 108 was constructed in concrete as part of MD 124 between 1925 and 1927. MD 420 was built as a concrete road from MD 124 west to Goshen Road in 1929 and 1930. The section of the highway east of MD 108 was paved in 1939 and designated MD 701. MD 701 was replaced by MD 420 in 1952. In 1959, MD 124 was moved to its present alignment, replacing its old course along Warfield Road, Laytonsville Road, and Brink Road. MD 420 replaced MD 124 along Brink Road; at the same time, the portion of MD 420 between MD 124 and Goshen Road was transferred to county maintenance. The remainder of MD 420 was removed from the state highway system in 1974.

MD 421

Maryland Route 421 was the designation for Travilah Road from MD 190 north to Glen Road near Travilah in southwestern Montgomery County. The highway was paved as a macadam road in 1929 and 1930. MD 421 was removed from the state highway system in 1959.

MD 426

Maryland Route 426 was the designation for Liverpool Point Road from the Potomac River east to MD 6 in Nanjemoy in western Charles County. The highway was constructed was a gravel road in two sections. The first was built from Nanjemoy, then known as Cross Road, west toward Liverpool starting in 1930. The route was extended to the Potomac River in 1933. MD 426 was removed from the state highway system in 1956.

MD 427

Maryland Route 427 was the designation for Chapel Point Road, which ran from the Port Tobacco River in Chapel Point State Park east to US 301 at Bel Alton in southern Charles County. The highway was constructed was a gravel road in two sections. The first was built from Bel Alton west toward Chapel Point starting in 1930. The route was completed to Chapel Point in 1933. MD 427 was removed from the state highway system in 1989.

MD 428

Maryland Route 428 was the designation for Penns Hill Road, which ran from MD 234 near Newport north to MD 6 in Dentsville in southern Charles County. The highway was built as a gravel road in three sections. The first section of MD 428 started construction at the Newport end in 1930. The second section was completed in 1933. The highway was completed from Newport to Dentsville in 1936. MD 428 was removed from the state highway system in 1956.

MD 429

Maryland Route 429 was the designation for Popes Creek Road, which ran from Popes Creek on the Potomac River north to US 301 at Faulkner in southern Charles County. The highway was built as a gravel road in two sections. The first section was constructed south from Faulkner in 1929 and 1930. Construction continued in 1930 and was completed to Popes Creek by 1933. MD 429 was removed from the state highway system in 1956.

MD 431

Maryland Route 431 was the designation for Cherryfield Road, which ran from MD 244 (now simply Drayden Road) south to the end of state maintenance in southern St. Mary's County. The highway was constructed as a gravel road by 1933. MD 431 was removed from the state highway system in 1956.

MD 432

Maryland Route 432 was the designation for Hawkes Road from Stringtown Road east to MD 27 near Clarksburg in northern Montgomery County. The highway was constructed as a concrete road in 1929. MD 432 was removed from the state highway system in 1959.

MD 433 (1930–1946)