The Missouri Coteau is a band of sharply rolling hills marked by potholes and grasslands within the Prairie Pothole Region. Coteau is the French word for "little hill." This unique landscape ranges from 10 to 50 miles wide. The potholes that give the region its name resulted from glaciation. As the ice sheet retreated some 10,000 years ago, it left behind uneven depressions. The ice eventually melted away, and the low-lying areas became wetlands. The region is now dotted with thousands of wetlands of different sizes and types. In the highest-density areas, there are more than 100 wetlands per square mile. These are prime nesting areas for waterfowl and provide habitat for a wide variety of other wildlife.