Prison escape

A prison escape (or prison break) is the act of an inmate leaving prison through unofficial or illegal ways. Normally, when this occurs, an effort is made on the part of authorities to recapture them and return them to their original detainers. Escaping from prison is also a criminal offense in some countries, such as the United States and Russia, and it is highly likely to result in time being added to the inmate's sentence, as well as the inmate being placed under increased security. Aggravating factors include whether or not violence was used.

Question: is it illegal to break out of prison
Answer: yes