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. Some time 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 600 and 699 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.