Londonderry is a town in western Rockingham County, New Hampshire, United States. The town is bordered on the north by the city of Manchester and on the east by the town of Derry. The population was 23,236 at the 2000 census. Londonderry is known for its apple orchards and is partial home to the Manchester-Boston Regional Airport. The more densely settled portion of town, where over 49% of the population resides, is defined as the Londonderry census-designated place (CDP) and roughly occupies the eastern and southern parts of town, around New Hampshire Route 102.