This is a list of bus routes operated by the Washington Metropolitan Area Transit Authority (WMATA), branded as Metrobus.
Many are the descendants of streetcar lines operated by the Capital Transit Company or its predecessors.
At one time, odd numbered routes were express routes, but that distinction has been abandoned.
Most Maryland and Washington, D.C., routes are grouped by their first digit.
When this system was laid out in 1936, the following clustering was used:[citation needed]