Arbor, NebraskaArbor is an unincorporated community in Lancaster County, Nebraska, United States.HistoryArbor may be named from Arbor [Lodge State Historical Park and Arboretum|Arbor Lodge], the estate of Julius [Sterling Morton], the 3rd United States [Secretary of Agriculture]. However, another source speculates that Arbor was likely named for the trees lining the town site. Arbor had a post office from 1894 until 1900.