Kingmaker in Eberron
Each hex on the map of the Stolen Lands is 12 miles across (between opposite corners) and covers just under 150 square miles of area. These hexes are provided not only as a way to help define the land (and eventually aid in defining the territory of the kingdom the PCs are destined to rule), but also as an aid in tracking travel through the Stolen Lands.
Use the chart to reckon the time it takes to travel across a hex versus exploring that hex fully. The dominant terrain type and any obstacles (such as water, encounters, or stopping to rest) will affect exploration time. All of the Stolen Lands are considered to be trackless (until roads are constructed!).
Water: A river varies from 50 to 500 feet in width. Infrequent bridges and fords that allow a river to be crossed are indicated on the map where they appear, but in most cases, travel across a river requires swimming or boating. If the PCs wish to try swimming, all members of the group must make Swim checks. If all members (and all mounts) make the check, then that particular river crossing doesn’t impact travel time through the hex. Otherwise, add 1 hour to the amount of time spent traveling for each failed Swim check. Lakes are calmer than rivers and may be navigated with an easier Swim check, but their larger size makes swimming across them dangerous.