 Auxiliary routes of MD 575 were designated between 2002 and 2004 as portions of the project to expand US 113 to a divided highway were completed.These routes are either old alignments of US 113 or service roads to provide access to private property or county highways compromised by the construction of the four-lane divided highway.Fourteen auxiliary routes were established, increasing in alphabetical order geographically from MD 575A in Showell to MD 575N just south of the Delaware state line.