The Keys (at least the accessible, commercial islands) are connected by US Highway 1. A useful and interesting "quirk" about the linearity of the Keys (and US-1) is that directions to establishments and attractions are locally described by the "Mile Markers" along US-1. If you ask someone how to get to a certain beach or hotel, they will tell you that it is at "Mile Marker 68.5"; many signs and brochures will say "MM 68.5" (of course, there is no mile marker 68.5, this just means that the hotel is halfway between mile markers 68 and 69). These numbers start at zero at the start of US-1 on Key West, so the numbers get larger as you go north.

The speed limits in the Keys are generally 45 MPH on the built-up Islands, and 55 MPH on the bridges and less built-up islands. There are areas (very built-up strips, or animal sanctuaries) where the speed drops to 35 MPH.