The Butler County Commission voted 4-1 Thursday to approve a redistricting plan that shuffles 210 voters into new districts.

A shift in the county’s population necessitated the change in order to comply with federal and state law.

Because Butler County operates under what is known as a single-member district, meaning each of the county’s five districts is represented by one commissioner, the law dictates that each district have the same number of voters.

“In an ideal world we would have the same number of people in each district, but since this isn’t an ideal world, the law allows for a deviation of 10 percent,” Butler County attorney Calvin Poole said.

“As long as the deviation is within 10 percent it is presumed constitutional. If it is over 10 percent that’s not to say that it is unconstitutional, but it is no longer presumed to be constitutional under federal law.”

The data from the latest census showed that Butler County’s current deviation is 14 percent, well above the allowed deviation. To bring the county’s districts into compliance, the Commission voted to move 148 voters from District 3 to District 4 and 62 people from District 5 to District 1.

First, Second and Merrimac Streets, previously a part of District 3, will now be included in District 4.

County Road 32 and County Road 79, previously a part of District 5, will now be a part of District 1.

District 2 will remain unchanged.

The changes will bring Butler County’s deviation to 9 percent.

“I’m pleased that we will be able to accomplish this with minor moves,” Commissioner Frank Hickman said when the plan was initially proposed. “The moves aren’t minor to those affected, but to only move (approximately) 200 people in a county of just under 21,000 isn’t bad.”

The voting precincts will remain unchanged for each district, although the 210 voters shifting districts will vote at a different precinct than they have in the past. The voting registrar will notify those whose voting precinct is changed once the Department of Justice approves the county’s plan.

The Butler County Board of Education is also expected to adopt a similar plan to bring its districts into line with the county’s districts.