The flattest U.S. state is Florida.

Why Florida is considered the flattest

Geographers and data analysts looking at overall relief (the difference between a state’s highest and lowest points, and how much its terrain changes) consistently rank Florida at the top for flatness. The whole peninsula sits very close to sea level, and there are no significant mountain ranges or steep uplands to break up the landscape.

Even when people assume Great Plains states like Kansas are flattest, quantitative terrain studies and elevation statistics show that Florida’s relief is smaller and its landforms are more uniformly low than those states. In everyday terms, if you drive across much of Florida, the road feels almost level for long stretches with only gentle, barely noticeable changes in height.

If you’re thinking of “as flat as it feels when you’re there,” and not just which state is lowest on average, Florida still comes out on top in modern rankings of flattest states.

TL;DR: Florida is widely recognized—by elevation data and terrain studies alike—as the flattest U.S. state.