Just like a carpenter can't finish a job without his tool belt, a good family researcher must have his or her own set of tools, and no tool kit is complete without a collection of maps.
There are many different types of maps: street maps, topographical maps, census maps, railway maps, insurance maps, old survey maps and highway maps, just to name a few. Each type of map can provide alternative views of the same area, allowing you to interpret why your ancestors ended up where they did.
A topographical map, for example, which shows the physical characteristics of an certain area, might give you an idea as to why you ancestor decided to settle in that specific place. Was he a farmer? Perhaps the land near the river was very fertile. Were there steep hills nearby? How would that affect the routes he chose to navigate the area?
Railway maps can help you determine which routes your ancestor used to travel the country. They might even indicate why your ancestor chose his home place.
Census maps are especially useful. Not only do they illustrate the physical boundaries of counties during a specific time period, but they also show how county lines shifted over time. This is key when searching for records. For example, perhaps your ancestor lived in one county, and he lived on the same property for his entire life, yet when you search that county for his will and estate records, nothing turns up. Why? By examining census maps, you would discover that while your ancestor never moved, the county line did, which is why his estate papers would be in an adjacent county.
Highway maps can also prove to be helpful when you're tracking ancestors. With few exceptions, many modern-day highways mirror the migration routes taken centuries earlier. These maps can give you an idea of the paths your ancestor might have taken when moving from one place to another.
There are many different components of a successful family researcher's tool kit, maps being only one of them. Don't underestimate the importance of studying and collecting different types of maps. One of them might just provide the missing piece to your family puzzle.