Burglary is generally the unlawful entry of a building or structure to commit a felony criminal offense (crime), theft, or assault. The definition of burglary varies from state to state (and in the federal system), and some states have different degrees of severity of the burglary offense—depending on the nature of the unlawful entry (type of building or structure), the intended purpose, and the illegal action taken by the defendant once inside the building or structure. In some states, breaking into an automobile, a coin-operated machine, or an ATM (automated teller machine) with the intent to commit a theft may also constitute the crime of burglary.

In Oregon, burglary is defined under ORS 164.215 and 164.225. The state recognizes different degrees of burglary. Burglary in the first degree (ORS 164.225) occurs when a person enters or remains unlawfully in a building with the intent to commit a crime therein, and either: the building is a dwelling, there is another person present in the building at the time of the crime, or the burglar uses or threatens to use a dangerous weapon. Burglary in the second degree (ORS 164.215), a less severe charge, involves unlawfully entering or remaining in a building with the intent to commit a crime, but without the aggravating factors required for first-degree burglary. Both degrees of burglary are felony offenses, with first-degree burglary being more serious and carrying stiffer penalties. The definition of 'building' in Oregon's burglary statutes is broad and can include structures not designed for residential use. Additionally, Oregon law does not specifically categorize the unlawful entry into an automobile or ATM with intent to commit theft as burglary, but such acts may be prosecuted under different statutes related to theft or criminal mischief.