AncestryDNA uses our Genetic Communities technology to help find places and populations that might be part of your past. These show up on your results as ancestral journeys. Journeys are groups of AncestryDNA members connected by DNA, likely because they descend from a population of common ancestors who lived in the same place around the same time, even if they no longer live where those ancestors once lived.
For example, some journeys trace their roots back to groups of people who were isolated geographically. Mountains, rivers, lack of roads, or other barriers made it likely that each new generation would marry someone who lived close to home. Others have their roots in groups who typically married others of the same religion or culture. In each case, these groups came to share a significant amount of DNA. Those groups, and their shared past, are reflected in their modern-day descendants who inherited some of that DNA.