Arrest or custodial arrest is the process in which the police take physical possession or custody of a person whom they have probable cause to believe committed a criminal offense. Arrest is distinguishable from other circumstances in which the police stop, detain, or otherwise interact with persons because it is generally the point at which a person is not free to leave or walk away from the police. Arrest is also the point at which some Constitutional rights and protections are provided to the accused. A person who is placed in handcuffs or otherwise physically restrained is clearly under arrest—but in some circumstances a person may be under arrest due to threats or intimidation from the police.

In Iowa, an arrest or custodial arrest occurs when law enforcement takes a person into physical custody based on probable cause that the individual has committed a criminal offense. This is a distinct legal threshold from other forms of police interaction such as investigatory stops or detentions. During an arrest, the individual is not free to leave and is subject to the control of the police. The point of arrest triggers certain Constitutional rights for the accused, such as the right to remain silent and the right to an attorney. The use of physical restraints like handcuffs typically signifies an arrest; however, an arrest can also occur if the police use threats or intimidation that effectively restrain a person's freedom to leave. Iowa law requires that arrests be made lawfully and that the rights of the accused are upheld throughout the process.