ATLANTA — Negotiations over the future of the Atlanta City Detention Center are continuing after the city and Fulton County failed to reach a deal before the county’s latest offer expired.

Atlanta Mayor Andre Dickens sent county commissioners a new $68 million counteroffer for the downtown facility after the county’s $56.5 million offer expired Monday.

In a letter to commissioners, Dickens called the county’s proposal a good starting point.

The county’s $56.5 million offer was based on a third-party appraisal. The city says other outside appraisers have valued the property at more than $140 million.

The latest counteroffer follows previous negotiations that included an $80 million offer from the city. County officials rejected higher-priced proposals from the city that also included additional financial commitments from the county.

Fulton County currently leases space at the Atlanta City Detention Center to temporarily house inmates, but that agreement expires at the end of the year.

The county is also planning a major overhaul of its main jail on Rice Street, a project expected to take years. Overcrowding and conditions at the facility have led the county to consider alternatives in the meantime.

The city says selling the detention center could eliminate the county’s possible plan to spend $140 million on a temporary facility.

A new lease at the Atlanta City Detention Center remains a possibility if a sale is not completed.

Fulton County commissioners could discuss the city’s latest $68 million proposal during their meeting Wednesday, Sept. 2.

WSB Radio’s Graham Carroll contributed to this story.