There are 10 US Post Offices in Pembina County serving a total of 6,324 residents equating to 632 residents per post office. It's estimated that approximately 10,094 packages are handled across the 10 county post offices annually. Pembina County is a county located in the U.S. state of North Dakota. At the 2010 Census its population was 7,413. The county seat is Cavalier. The area along the Pembina and Red rivers was long inhabited by various indigenous peoples. At the time of European contact, the dominant tribe were the Assiniboine and the Lakota (or Sioux, as the French colonists called them). Later the Ojibwe (or Chippewa) migrated into the area from the east and became the dominant tribe. The people had a long trading relationship with French colonists and supported them during the Seven Years' War against Great Britain. By the time of the War of 1812, the Ojibwe were allied with the British against the United States, hoping to forestall or slow European-American settlers' encroaching on their territory. During the first half of the nineteenth century, continuing conflicts between the Lakota and Chippewa along the Red River slowed European-American settlement. The Chippewa pushed the Lakota to the west and became dominant in the area. The county was created by the 1866\u20131867 Dakota territorial legislature, and was organized on August 12, 1867. \"Pembina\" is derived from the Chippewa term for high-bush cranberry, which grew in abundance along the Pembina River. The city of Pembina, the oldest European-American settlement in the state, was the county seat from 1867 to 1911. The seat was relocated to Cavalier. Cavalier Air Force Station and Icelandic State Park are both located in Pembina County. The first Icelandic immigrant settlement in present-day North Dakota was in Pembina County in the late 1870s, when a colony of settlers from Iceland moved into the county from the New Iceland homesteads near Lake Winnipeg."