Why are two range lights placed at different elevations?

Range lights are placed at different elevations to provide mariners with accurate directional guidance when navigating through ports, harbors, or estuarial approaches. By positioning two fixed lights at different heights and separated by a specific distance, they create a visual alignment for the navigator.1

When a vessel is on the correct course, the two lights appear vertically aligned, one directly above the other. If the vessel drifts off course, the lights will appear to shift horizontally relative to each other, allowing the navigator to make immediate adjustments to return to the intended path. This method serves as a highly sensitive and reliable tool for maintaining a precise heading in restricted or complex coastal waters.12