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The Bay of Fundy is a coastal basin in eastern Canada notable for large tidal ranges. Its geometry and the dynamical response of the connected bay system strongly amplify the incoming semidiurnal tide.

The important physical idea is forced motion of a basin: water depth, shape and friction determine its natural response, while the external astronomical tide supplies the drive. Large range is not a direct local measurement of an unusually strong gravitational field. Range also varies with location and the spring-neap cycle, so one quoted maximum does not characterize every observation.

The tidal range is the difference in sea-surface height between a specified high tide and the neighboring low tide, measured relative to the same datum. A high-water level of $4.2\mathrm{m}$ and low-water level of $1.1\mathrm{m}$ give a range of $3.1\mathrm{m}$.

For a sinusoidal tide $\eta (t)=A\cos \omega t$, the range is $2A$, not the amplitude $A$. Interference between lunar and solar tidal contributions produces larger spring ranges and smaller neap ranges. Coastline geometry, water depth and resonance modify the local response, so the tidal range cannot be inferred from astronomical forcing alone.