Bridge Clearance Lookup
Find the vertical clearance under any US bridge. For drawbridges, see the opening schedule, VHF channel, and how to request an opening. 927 bridges, 187 drawbridges.
Drawbridges with opening schedules
Movable bridges with US Coast Guard operating rules, VHF channel, and closed clearance.
Browse bridges by state
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How to read bridge clearance
Vertical clearance is the height between the water and the underside of a bridge. On US charts it is referenced to mean high water (MHW), so the real clearance is lower near high tide and during storm surge, and higher at low tide. Compare it to your boat's air draft (waterline to the highest fixed point, antennas included) and keep a safety margin.
A drawbridge (bascule, swing, lift, or pontoon) opens for vessels that can't clear it closed. To request an opening you hail the bridge tender on VHF-FM Channel 13 (the standard drawbridge channel), sound the required horn signal, or call the posted number. Many drawbridges only open on a schedule or need advance notice, all set by the US Coast Guard in 33 CFR Part 117. Each drawbridge page here shows its specific rule where one exists.
Clearances come from NOAA S-57 electronic charts; drawbridge schedules come from the Coast Guard regulations. Both are references, not a substitute for the posted clearance gauge and current chart. When in doubt, wait for the tender.
You've got the data. Now put it on your chart.
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