The Queens Chapel Road Line, designated Route R4, is a daily bus route operated by the Washington Metropolitan Area Transit Authority between the Highview Apartment Complex in Hyattsville, Maryland and Brookland–CUA station of the Red Line of the Washington Metro.

During light or moderate snowfall detours, route R4 would terminate at Hyattsville Crossing station with no service operating to Highview.

In 1962,[4] G7 was created as a brand new DC Transit Route to operate as part of the "Prince George's Express" Line between Highview and Potomac Park, via Highview Terrace, Dean Drive, Northwest Drive, Toledo Terrace, Prince George's Plaza Shopping Center, Belcrest Road, Queens Chapel Road, Michigan Avenue NE, 4th Street NE, Lincoln Road NE, Rhode Island Avenue NE/NW (U.S. Route 1), 6th Street NW, Constitution Avenue NW, Virginia Avenue NW, and C Street NW.

G5 was eventually created as a DC Transit bus route to operate as prt of the "Prince George's Express" Line alongside Route G7, between Highview and Potomac Park, following most of the exact same routing only with the exception of going by Bureau of Engraving before continuing on to its Potomac Park, shortly around 1973 when WMATA took over DC Transit and other bus companies operating across the DC Area and merged them all together to form its own Metrobus System.

On February 19, 1978, Route R2 was truncated to only operate between the Brookland–CUA station and Great Oaks Center (Calverton).

[7] When the site of where the new Mosaic Apartments next to Prince George's Plaza (now Hyattsville Crossing) station, were being built, route R4 was rerouted to operate along East West Highway and turning onto Belcrest Road going to Highview from Prince George's Plaza (now Hyattsville Crossing) station due to the construction.

During the COVID-19 pandemic, Route R4 was reduced to operate on its Saturday supplemental schedule beginning on March 16, 2020.