SR 99 - NB Duwamish River Bridge - Select Grid Deck Replacement - Detours

On nights that the northbound SR 99 Duwamish River Bridge is closed, several detour options will be available:

  • Lower Spokane Street Bridge (could close for emergencies)
  • South Park Bridge
  • East Marginal Way South Bridge
  • Tukwila International Boulevard Bridge
  • Interstate 5

A map showing alternatives to the northbound SR 99 Duwamish River Bridge.
The northbound SR 99 Duwamish River Bridge, also known as the First Avenue South bridge, will close for up to 14 nights in July and August 2020 as crews replace sections of the metal deck.