City Council is planning to revise its recently approved redistricting plan to ensure incarcerated Philadelphians are counted in their home districts, instead of the city jails or state prisons in which they were held at the time of the 2020 census.

Council President Darrell L. Clarke confirmed that his office is working with Mayor Jim Kenney’s administration to adjust its population data to tackle the issue known as “prison gerrymandering,” a redistricting practice growing more common that is aimed at ensuring voters in districts with correctional facilities aren’t overrepresented.

It’s unclear when legislation will be introduced to amend the redistricting bill that Council approved two weeks ago, but it is expected to be in place for the 2023 election cycle, when all Council seats and an open mayor’s race will be on the ballot.

“Once all the data is in hand, it will be sent to a vendor to begin incorporating it into our redistricting map,” Clarke spokesperson Joe Grace said. “It will happen as expeditiously as possible, but we want to make sure it’s done correctly and accurately.”

Unlike in state legislatures, where the populations of rural districts with large prisons can shift dramatically depending on whether they include people incarcerated there, the changes to the recently approved Council district boundaries will likely be minimal.

The roughly 7,000 Philadelphians who were counted in state prisons in 2020 will be included in the Council districts of their last listed address. But because they will add population to all of Council’s districts, it’s unlikely any one district will gain enough to warrant a significant redrawing of the lines. Inmates serving time for felonies are prohibited from voting until after they are released.

The biggest change will likely result from the redistribution of the several thousand people who were counted in the city’s State Road jail complex in the Lower Northeast. The city jails typically hold just under 5,000 people, but the number may have been lower at the time of the census.

Those facilities essentially add population to Council’s 6th District, which was recently vacated by former Councilmember Bobby Henon after his conviction on federal corruption charges.

Council has 10 members who represent geographic districts and seven who are elected citywide. Each district contains about 160,000 of the city’s 1.6 million residents.

Clarke, who represents the North Philadelphia-based 5th District, led the once-a-decade redistricting process, negotiating behind close doors with lawmakers to produce a map that largely follows the contours of the current districts with small changes to account for shifts in populations.

Council held one public hearing on Clarke’s proposal, and many residents urged lawmakers to tackle prison gerrymandering, as the state Legislative Reapportionment Commission already has for the Pennsylvania General Assembly. Despite good-government groups like the Committee of Seventy having previously called on Council to tackle the issue, Clarke in the hearing sounded surprised by the level of support for using prison-adjusted data.

Although he insisted that Council first approve a map without the new data in order to meet a Feb. 12 deadline imposed by the city Home Rule Charter, Clarke opened the door to Council taking the unusual step of revising it after it was adopted.

“The issue matters, we’ve clearly heard residents and advocates, and Council intends to do it the right way,” Grace said.