HARRISBURG — The Wolf administration said Thursday it will close Pittsburgh State Prison to save money at a time when inmate numbers are dropping and the state faces a huge budget deficit, but has opted against an earlier plan to also shut down a second facility.

Corrections Secretary John Wetzel said the 1,900-inmate prison will close by the end of June, producing a net annual savings of about $81 million.

The administration had previously said it was considering closing two prisons from a list of five — Pittsburgh, Frackville, Mercer, Retreat and Waymart — but ultimately decided to shut down just one.

Pittsburgh, which first opened in 1882, posed a challenge to shut down because it serves as a diagnostic and classification center, as well as housing medical services such as a cancer treatment unit. Wetzel said those issues were worked out.

The state inmate population is about 49,000 and has fallen by 2,400 since mid-2012. There are currently 26 prisons.

The plan also involves doing away with about 1,500 halfway-house beds.