Arnold is a suburb of Annapolis and a census-designated place (CDP) in Anne Arundel County, Maryland, United States. The population was 23,106 at the 2010 census. Neighborhoods straddle College Parkway and Maryland Route 2 (Ritchie Highway). Arnold is located on the scenic Broadneck peninsula. The ZIP code is 21012.
Native Americans are known to have resided in the region in pre-Columbian times based on artifacts found in the Ulmstead Point area dating back to the Archaic period (5000–1500 BC). Later tribes that have been in the area include the Algonquin tribes, among others. However, when Captain John Smith arrived in the area in 1608, he reported no Natives.
The early settlement of Arnold, an area between the Magothy and Severn rivers, began with the farm of John Arnold. He was a veteran of the War of 1812, who acquired 300 acres (1.2 km2) on the north side of the Severn River.