in Iowa was generally sparse before the lands opened in 1833. Most of the immigrants who came shortly after this time were from other states, especially Illinois, Indiana, Ohio, Missouri, Kentucky, and Tennessee, and to a lesser extent New York, Pennsylvania, Virginia, and the Carolinas. The great majority of newcomers came in family units. Most families had resided in at least one additional state between the time they left their state of birth and the time they arrived in Iowa. Sometimes families had relocated three or four times before they reached Iowa. At the same time, not all settlers remained here; many soon moved on to the Dakotas or other areas in the Great Plains. The settlers soon discovered an environment different from that which they had known back East. Most northeastern and southeastern states were heavily timbered; settlers there had material for building homes, outbuildings, and fences. Moreover, wood also provided ample fuel. Once past the extreme eastern portion of Iowa, settlers quickly discovered that the state was primarily a prairie or tall grass region. Trees grew abundantly in the extreme eastern and southeastern portions, and along rivers and streams, but elsewhere timber was limited. In most portions of eastern and central Iowa, settlers could find sufficient timber for construction of log cabins, but substitute materials had to be found for fuel and fencing. For fuel, they turned to dried prairie hay, corn cobs, and dried animal droppings. In southern Iowa, early settlers found coal outcroppings along rivers and streams. People moving into northwest Iowa, an area also devoid of trees, constructed sod houses. Some of the early sod house residents wrote in glowing terms about their new quarters, insisting that "soddies" were not only cheap to build but were warm in the winter and cool in the summer. They did not praise the bugs, the smells, or the ever-present dirt, dampness and darkness. Settlers experimented endlessly with substitute fencing materials. Some residents built stone fences; some constructed dirt ridges; others dug ditches. The most successful fencing material was the osage orange hedge until the 1870s when the invention of barbed wire provided farmers with satisfactory fencing material. As the settlers came into Iowa, they naturally established communities. Significant of these were Burlington, Dubuque, Davenport, Keokuk, Fort Madison, and Muscatine. By 1836, when the first census was taken in Iowa, there were 10,531 inhabitants. This rapid immigration was but