The Red Line is a proposed east–west transit line for Baltimore, Maryland. The original project was granted federal approval to enter the preliminary engineering phase and the Maryland Transit Administration had spent roughly $300 million in planning, design and land acquisition, until Maryland Governor Larry Hogan declared his intent to not provide state funds for the project and shift state funding to roads in suburban areas. The original Red Line had been projected to cost roughly $1.6 billion, $900 million of which would have been guaranteed federal funding. Its construction had been estimated to begin in late 2015–early 2016, subject to funding, with a completion date set for late 2021–early 2022.

The Maryland Transit Administration (MTA) is a state-operated mass transit administration in Maryland, and is part of the Maryland Department of Transportation. The MTA operates a comprehensive transit system throughout the Washington-Baltimore metropolitan area. There are 80 bus lines serving the Baltimore Metropolitan Area, along with rail services that include the Light Rail, Metro Subway, and MARC Train. In 2023, the system had a ridership of 52,922,000, or about per weekday as of the fourth quarter of 2023.