As far as the Peninsula goes, if you drew a line from Crystal River to New Smyrna Beach, about 110 miles. This is the part of the state where it bottlenecks before getting into the panhandle.
The narrowest point of the Tennessee River is 10 1/2 ft wide.
The merced river's narrowest points are 5 to 6 ft wide.
3 miles
26km at chelyabinks
The body of water that separates the United States from Cuba is the Straits of Florida. It is about 90 miles wide at its narrowest point.
Manhattan is 0.8 miles wide at its narrowest point, and 2.3 miles at its widest.
The narrowest point in the UK runs from Hadrian's Wall to the English East Coast. It is 70 miles wide, or 274 kilometers.
At its narrowest point Idaho is 50 miles wide.
94 km at Illapel
Scotland is right around 275 miles long. It is 25 miles wide at its narrowest point and 155 miles wide at its broadest point.
The narrowest point of the channel is the Strait of Dover which is 34 km wide.
Auckland is at its narrowest point approximately 2.5 kilometers (about 1.6 miles) wide. This narrow section is located between the Manukau Harbour to the west and the Waitematā Harbour to the east. This geographical feature contributes to Auckland's unique positioning as a city straddling two harbors.