Fords have been important throughout history because they allow people to cross rivers. A fording point is not that common, so where one occurs people normally come from far and wide to that place to cross the river.

As you might imagine, controlling a ford is a good way of guarding a region, so, in the past, castles and forts were built by fords.

If people come together to cross at a ford, then there are more people than normal gathered together and so there is a better chance of selling things to them. This is why many towns and cities grew up at fords (although nowadays the ford is almost certainly replaced with a bridge).