Yes, OJ Simpson is still in prison. He is currently serving time at the Lovelock Correctional Facility, which is located in Nevada.
He was found NOT guilty of the murder of his ex wife and the mother of his children, Nicole Brown Simpson. He was enjoying life as a free man for quite some time, even though most people believe he got away with murder.
The good news is that he is locked up now and will remain in jail for at least a few more years. However, the reason he has been locked up is not related to the Nicole Brown Simpson murder. Instead, he went to prison after being convicted of an armed robbery that took place at the Palace Station Casino. He was attempting to steal HIS OWN memorabilia, which is ridiculous!