The Quad Cities is a group of five cities straddling the Mississippi River on the Iowa–Illinois boundary, in the United States. These cities, Davenport and Bettendorf (in Iowa) and Rock Island, Moline, and East Moline (in Illinois), are the center of the Quad Cities Metropolitan Area, which, as of 2011, had a population estimate of 381,342. The Quad Cities is midway between Minneapolis on the north and St. Louis on the south; Chicago on the east and Des Moines on the west. The area's 300-mile market of nearly 36.5 million people comprises nearly 15% of the nation's population. This makes it the largest 300-mile market west of Chicago.

The name "Quad Cities" for a group of five is based on the history of the community.

Before European settlers came to inhabit the Quad Cities, the confluence of rivers had attracted many varying cultures of indigenous peoples, who used the waterways and riverbanks for their settlements for thousands of years. At the time of European encounter, it was a home and principal trading place of the Sauk and Fox tribes of Native Americans. Saukenuk was the principal village of the Sauk tribe and birthplace of its 19th-century war chief, Black Hawk. In 1832, Sauk chief Keokuk and General Winfield Scott signed a treaty in Davenport after the US defeated the Sauk and their allies in the Black Hawk War. The treaty resulted in the Native Americans' ceding 6 million acres (24,000 km²) of land to the United States in exchange for a much smaller reservation elsewhere. Black Hawk State Historic Site in Rock Island preserves part of historic Saukenuk and is listed on the National Register of Historic Places.

Quad may refer to:

Most major American universities, as well as many smaller colleges, have an open area of campus surrounded by buildings commonly known to the students as "The Quad". Some of these "quads" have been officially designated with formal names.

A police officer (also known as a policeman or policewoman, and constable in some forces, particularly in the United Kingdom and other Commonwealth nations) is a warranted employee of a police force. In the United States, "officer" is the formal name of the lowest police rank; in many other countries "officer" is a generic term not specifying a particular rank, and the lowest rank is often "constable". Police officers are generally charged with the apprehension of criminals and the prevention and detection of crime, and the maintenance of public order. Police officers may be sworn to an oath, and have the power to arrest people and detain them for a limited time, along with other duties and powers.

Some police officers may also be trained in special duties, such as counter-terrorism, surveillance, child protection, VIP protection, and investigation techniques into major crime, including fraud, rape, murder and drug trafficking.

Responsibilities of a police officer are varied, and may differ greatly from within one political context to another. Typical duties relate to keeping the peace, law enforcement, protection of people and property, and the investigation of crimes. Officers are expected to respond to a variety of situations that may arise while they are on duty. Rules and guidelines dictate how an officer should behave within the community, and in many contexts restrictions are placed on what the uniformed officer wears. In some countries, rules and procedures dictate that a police officer is obliged to intervene in a criminal incident, even if they are off-duty. Police officers in nearly all countries retain their lawful powers, while off duty.