South Lake Union
Sound Transit is studying the following station alternatives in South Lake Union.
- Tunnel Harrison Street Station (associated with the 5th Avenue and Harrison Alternative) (Preferred alternative)
- Tunnel station under Harrison Street between Aurora Avenue North and Dexter Avenue North
- Tunnel Mercer Street Station (associated with the 6th Avenue and Mercer Alternative)
- Tunnel station on the north side of Mercer Street between Taylor Avenue North and State Route 99 / Aurora Avenue North
View the Station Planning Progress Report for more details (7 MB).
Tunnel Harrison Street Station (associated with the 5th Avenue and Harrison Alternative) (Preferred alternative )

The text below describes the image above
Map of the South Lake Union – Tunnel Harrison Street Station alternative with boundaries of SR 99/Aurora Avenue North to the north, Eighth Avenue North to the east, Thomas Street to the south, and Taylor Avenue North to the west. The tunnel guideway for this new station runs east and west under Harrison Street with a station platform located between Seventh Avenue North and Dexter Avenue North. Station entry points for this station alternative include three entrances on the northwest corner of the Dexter Avenue North and Harrison Street crossroad and two entrances on the southwest corner of the Seventh Avenue North and Harrison Street crossroad. A pedestrian-focused realm will be implemented around the potential station. The borders of this realm are located with borders of Harrison Street to the north, Dexter Avenue North to the east, Thomas Street to the south, and Sixth Avenue North to the west. Existing crosswalks to the proposed South Lake Union – Tunnel Harrison Street station area are located at the crossroads of Sixth Avenue North and Harrison Street, Seventh Avenue North and Harrison Street, Dexter Avenue North and Harrison Street, and Seventh Avenue North and Thomas Street. Current bus routes run east and west on Harrison Street and north and south from Seventh Avenue North onto SR 99/Aurora Avenue North and Dexter Avenue North. Active bus bays include a location on each side of Harrison Street east and west of Seventh Avenue North, on each side of Seventh Avenue North between Harrison Street and Thomas Street, and on each side of Dexter Avenue North between Republican Street and Harrison Street. A paratransit stop is located on the northwest corner of Harrison Street and Dexter Avenue North adjacent the east station entrance. Existing bicycle facilities exist north and south on Dexter Avenue North. Future bicycle facilities exist east and west on Thomas Street. Existing bicycle and personal mobility storage is located on the northwest corner of the Seventh Avenue North and Thomas Street crossroad. Pick-up and drop off sites for automobiles are located on each side of Sixth Avenue West south of Harrison Street. Parks and public space are located at International Fountain Mall and South Fountain Lawn at Seattle Center east of Climate Pledge Arena and Second Avenue North. Potential transit-oriented development located on the southwest corner of the Seventh Avenue North and Harrison Street crossroad.

Pedestrian Access – Key features
- West entrance on the southwest corner of the SR 99/Aurora Avenue North and Harrison Street intersection
- East entrance on the northwest corner of the Dexter Avenue North and Harrison Street intersection
Key
Station location
Station entry area

Bike Access - Key features
- Bike lanes on Dexter Avenue North and Thomas Street
- Access to the Cheshiahud Lake Union Loop Trail via protected bike lanes on Dexter Avenue North, Roy Street and 9th Avenue North
- Bike lockers and racks adjacent to the west station entrance (access from Thomas Street)
Key
Station location
Bike storage area
Existing bike route
Planned bike route

Transit Access – Key features
- Bus routes on Harrison Street, Dexter Avenue North and 7th Avenue North (known as State Route 99 / Aurora Avenue North north of Harrison Street)
- Bus stops on Harrison Street between Dexter Avenue North and 6th Avenue North
- Bus stops on Dexter Avenue North north of Harrison Street
Key
Station location
Bus stop
Bus route
Tunnel Mercer Street Station (associated with the 6th Avenue and Mercer Alternative)

The text below describes the image above
Map of the South Lake Union ‐ Tunnel Mercer Street Station alternative with boundaries of Valley Street to the north, Dexter Avenue North to the east, Harrison Street to the south, and Fifth Avenue North to the west. The tunnel guideway for this new station runs east and west north adjacent Mercer Street with a station platform located between Taylor Avenue North and SR 99/Aurora Avenue North. Station entry points for this station alternative include two entrances on the northwest corner of the SR 99/Aurora Avenue North and Mercer Street cross-section and one entrance on the northeast corner of the Taylor Avenue North and Mercer Street crossroad. A pedestrian-focused realm will be implemented around the potential station. The borders of this realm are located with Roy Street to the north, Dexter Avenue North to the east, Mercer Street to the south, and Taylor Avenue North to the west. Existing crosswalks to the proposed South Lake Union ‐ Tunnel Mercer Street station area are located at the crossroads of Fifth Avenue North and Mercer Street, Taylor Avenue North and Mercer Street, and Dexter Avenue North and Mercer Street. Current bus routes run east and west on Mercer Street north and south on Taylor Avenue North, SR 99/Aurora Avenue North, Dexter Avenue North, and north and south on Fifth Avenue North up to Mercer Street. Active bus bays include a location on each side of Fifth Avenue North between Mercer Street and Republican Street, and on each side of Dexter Avenue North between Roy Street and Mercer Street. A paratransit stop is located on the west side of Taylor Avenue North adjacent the East station entrance. Existing bicycle facilities exist north and south on Dexter Avenue North, north and south on Fifth Avenue North from Republican Street to Roy Street, and north and south on Taylor Avenue North from Mercer Street to Roy Street. Future bicycle facilities exist north and south on Fifth Avenue North south of Republican Street. Existing bicycle and personal mobility storage is located on the northeast corner of the Taylor Avenue North and Mercer Street crossroad as well as on the northwest corner of the SR 99/Aurora Avenue North and Mercer Street crossroad. Pick-up and drop off sites for automobiles are located on each side of Roy Street between Taylor Avenue North and Sixth Avenue North, and on the northeast corner of the Sixth Avenue North and Roy Street crossroad. A potential transit-oriented development is located on the block north of Mercer Street and south of Roy Street between Taylor Avenue North and SR 99/Aurora Avenue North.

Station context
Tunnel station on the north side of Mercer Street between Taylor Avenue North and State Route 99 / Aurora Avenue North
Key
Station location

Pedestrian Access – Key features
- West entrance on the northeast corner of the Taylor Avenue North and Mercer Street intersection
- East entrances at street level on northeast corner of Mercer Street and at street level of State Route 99 / Aurora Avenue North
Key
Station location
Station entry area

Bike Access - Key features
- Bike lanes on Dexter Avenue North, Roy Street, 5th Avenue North and the north side of Mercer Street (between 5th Avenue North and Dexter Avenue North)
- Access to the Cheshiahud Lake Union Loop Trail via protected bike lanes on Dexter Avenue North, Roy Street and 9th Avenue North
- Bike lockers and racks adjacent to the station entrances (access from Roy Street or Mercer Street)
Key
Station location
Bike storage area
Existing bike route
Planned bike route

Transit Access – Key features
- Bus routes on 5th Avenue North, Dexter Avenue North and State Route 99 / Aurora Avenue North
- Bus stops on 5th Avenue North south of Mercer Street
- Bus stops on Dexter Avenue North north of Mercer Street
Key
Station location
Bus stop
Bus route