Early humans consistently settled near fresh water, in areas where different landscapes met, and close to natural shelter like caves and rock overhangs. These weren’t random choices. For millions of years, the factors that determined where people lived came down to a short list: reliable water, diverse food sources, manageable terrain, and protection from the elements.
Rivers and Fresh Water Came First
More than any other single factor, proximity to water shaped where early humans set up camp. Rivers provided drinking water, attracted animals that could be hunted, supported edible plants along their banks, and later made agriculture possible. Studies of early settlement patterns consistently find that distance to the nearest water source is one of the strongest predictors of where people chose to live. Gentle slopes, moderate elevation, good soil, and abundant sunlight also mattered, but water was the non-negotiable requirement.
This is why some of the most significant early settlements cluster around major river systems. Mesopotamia, the region between the Tigris and Euphrates rivers in modern-day Iraq, Syria, Turkey, and Iran, became one of the cradles of civilization precisely because seasonal flooding deposited fertile soil across the valley floors, creating an oasis of farmable land in an otherwise dry landscape. The presence of dependable water created the conditions for both agriculture and the first urban settlements.
Where Two Landscapes Meet
Early humans showed a strong preference for settling at ecotones, the boundary zones where two different habitats overlap. The edge between forest and open grassland was especially attractive. These transition zones offered the best of both worlds: forests provided shelter, firewood, and plant foods, while open grasslands made travel easier, improved visibility for spotting predators or prey, and supported large herds of grazing animals.
Research on the earliest migration routes of modern humans out of Africa confirms that people repeatedly gravitated toward forest-grassland ecotones. These border zones tend to support higher biodiversity than either habitat alone, which meant a wider variety of food sources in a smaller area. For mobile hunter-gatherers who needed to find enough calories every day, that diversity was a survival advantage.
Caves, Rock Shelters, and Open-Air Camps
The popular image of “cavemen” is only partly right. Early humans did use caves and rock shelters extensively, with hearth evidence at cave sites in Africa, Europe, and Asia dating back to the late Lower Paleolithic period, roughly 300,000 years ago or earlier. Caves offered obvious benefits: natural walls and ceilings that blocked wind, rain, and cold. But caves also came with limitations. Lighting a fire inside a cave during summer could fill the interior with smoke down to about half a meter from the ground, making it nearly unlivable. In winter, temperature differences between inside and outside air caused smoke to rise higher, making cave occupation more practical in cold months.
Open-air camps were just as common, and in many regions more so. Among the San people of southern Africa, camps were organized with a central hearth placed outside the huts. In the circumpolar north, traditional Sámi tents placed the hearth inside beneath an open chimney at the top. The type of shelter early humans used depended heavily on local climate, season, and what materials were available. Caves were valuable where they existed, but most of the Earth’s surface doesn’t have them, and people settled those areas too.
Climate Swings Drove Migration
Early human settlement patterns weren’t static. They shifted dramatically with the planet’s climate. During the Pleistocene, which lasted from about 2.6 million to 11,700 years ago, repeated glacial cycles expanded and contracted ice sheets, raised and lowered sea levels, and turned green corridors into deserts and back again. Modeling of early human dispersal out of Africa identifies at least four major migration waves across the Arabian Peninsula and into the Levant: roughly 106,000 to 94,000, 89,000 to 73,000, 59,000 to 47,000, and 45,000 to 29,000 years ago. Each wave corresponded to periods when increased rainfall turned arid stretches of northeastern Africa and Arabia into vegetated corridors that people could cross.
These long orbital-scale climate swings, driven by changes in Earth’s tilt and orbit around the sun, played the dominant role in shaping where human populations concentrated across the globe. Shorter, more abrupt climate shifts had more limited regional effects. When conditions deteriorated in one area, people moved to refugia, pockets of livable habitat that maintained water and food resources even during harsh periods.
Coastlines and Marine Resources
Coastal areas attracted early settlers for a straightforward reason: the ocean is an enormous, reliable food source. Shellfish, fish, seabirds, and marine mammals provided calories that didn’t depend on rainfall or seasonal plant growth. One prominent hypothesis, sometimes called the “kelp highway,” proposes that early humans entered the Americas by following the Pacific coast, using productive kelp forest ecosystems as a food corridor. Stone tool analysis suggests that early seafarers may have moved into the Americas from the northwestern Pacific Rim, including what is now Hokkaido in Japan, as early as 20,000 years ago.
Archaeological sites along the coast of British Columbia, including Calvert Island where human footprints date to between 13,300 and 12,700 years ago, provide physical evidence of early coastal occupation. In South America, Monte Verde in Chile is one of the oldest known sites in the Americas. That said, coastal settlement evidence is often difficult to find because sea levels have risen dramatically since the last ice age, submerging many ancient shorelines under meters of water.
The Shift to Permanent Villages
For most of human history, settlements were temporary. Groups moved with the seasons, following animal herds and ripening plants. The transition to permanent year-round occupation happened gradually. One of the earliest known examples is Ohalo II, a site on the shore of the Sea of Galilee in Israel that was discovered in the late 1980s when a drought dropped water levels. Radiocarbon dating placed this small, year-round hunter-gatherer camp at about 23,000 years old, thousands of years before farming began.
True agricultural villages appeared much later, clustering in the Fertile Crescent, a band of territory arcing from the Persian Gulf through modern Iraq, Syria, and down through the Levant to the Mediterranean. This region had a unique combination of wild grains that could be domesticated (wheat, barley) and animals suited to herding (sheep, goats, cattle). Jericho, in the modern Palestinian territories, and sites in Syria and Jordan are among the earliest known permanent agricultural settlements, dating to roughly 10,000 to 11,000 years ago. The shift from moving camp every few weeks to staying in one place permanently changed everything about human society, from population density to social hierarchy to the diseases people caught.
Africa as the Starting Point
The very earliest human ancestors settled in eastern and southern Africa. The oldest potential hominin fossils, including Orrorin tugenensis, date back at least 6 million years. In South Africa, the Sterkfontein caves in Gauteng province have yielded Australopithecus fossils that may be as old as 3.7 million years. Drimolen Main Quarry, also in South Africa, produced what researchers consider the oldest known skull with clear features of Homo erectus, the species most closely associated with the first major expansion out of Africa.
Sites like Olduvai Gorge in Tanzania, with deposits spanning over a million years of occupation, show that early humans returned to the same resource-rich locations generation after generation. These African sites share the same basic features that would attract human settlement everywhere else on the planet: water, diverse food sources, moderate terrain, and some form of natural shelter.