Arnold, a census-designated place (CDP) in Anne Arundel County, Maryland, United States, located just outdoor of the state’s capital, Annapolis. It is located 18.78 miles south of Baltimore, and 29.97 miles east of Washington, D.C. The population was 23,106 at the 2010 census. Neighborhoods straddle College Parkway and Maryland Route 2 (Ritchie Highway). Arnold is located upon the scenic Broadneck Peninsula. The ZIP code is 21012. It is bordered by Severna Park to the northwest, Cape Saint Claire to the southeast, Annapolis to the southwest, and Lake Shore (a CDP within Pasadena) to the northeast.

Native Americans are known to have resided in the region in pre-Columbian epoch based upon artifacts found in the Ulmstead Point area dating support 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 Place in 1608, he reported no Natives.

The early pact of Arnold, an area between the Magothy and Severn rivers, began like the farm of John Arnold. He was a veteran of the War of 1812, who acquired 300 acres (1.2 km) on the north side of the Severn River. One of his sons, Thomas Arnold, inherited the land, later dynamic as the local station master for the Baltimore and Annapolis Short Line Railroad.

Residents know the Place to have been house to a racetrack in the present-day Revell-Downs planned community and even a rollercoaster and boardwalk in Mago Vista Beach.