MARIETTA - With help from the state reapportionment office in downtown Atlanta, Cobb Chairman Tim Lee has come up with two preliminary maps that attempt to balance population between northwestern Cobb, which has seen strong growth, and northeastern Cobb.

The first proposed map would add the entire city of Acworth, which is currently in District 1, to District 3.

The second proposal would add the city of Kennesaw north of U.S. 41 and Bells Ferry Road, including the Town Center area, to District 3. Acworth would remain a part of District 1.

Both maps leave Districts 1 and 4 largely unchanged, with a few lines south of Marietta and west of U.S. 41 being "cleaned up," Lee said. District 2 would also gain some more of the city of Marietta south of Sandy Plains road and a section south of Roswell Road.

"A judge had to draw the district lines in 2002," Lee said. "District 4 was looked at closely in that, so ... we left it alone."

Congressional and local government voting boundaries are redrawn every 10 years.

Districts must be divided as equally as possible based on overall population, not voting age population or registered voters.

Since Cobb's total population is 688,144, the ideal value for each district is 172,019.

District 1, for example, has 24,000 more residents than the ideal number, while District 3 is 16,763 under the target population at 155,256.

Commissioner Helen Goreham represents District 1, and Commissioner JoAnn Birrell represents District 3.

District 4, which is represented by Commissioner Woody Thompson, was only over the target by 2,400. District 2, represented by Commissioner Bob Ott, will need to pick up about 9,000 residents to reach the target.

In addition to equally distributing the population and following the Voting Rights Act, other factors must be considered in redistricting, Lee said.

"There are some criteria we try to follow," he said. "It has to be contiguous, have compactness, try to follow natural boundaries and try not to split precincts. And it's perfectly legal to protect incumbents."

The second proposed map fits those elements best, so far, Lee said.

"Not only does it look better, but it's statistically better," he said.

Commissioners will have to agree on a map before the process can continue.

In the next few weeks, commissioners will go in pairs to the reapportionment office to see how the process works and make adjustments if necessary.

"It's hard to tell from the maps which specific neighborhoods will be affected," said Ott, who is up for reelection in 2012. "(At the reapportionment office,) you can zoom in down to the street."

Goreham said there was less movement of lines on the proposed maps than she imagined there would be.

"Which to me is a good thing," she added. "Right now the preliminary map looks fair in its adjustment. We'll be traveling down ourselves to get a clearer view so we can be even more confident in the process."

Birrell said she thinks both options are fair and reasonable.

"I'm pretty comfortable with either one, but I want to wait until we go down to the redistricting office together to look at the maps and population count and see it first-hand before I weigh everything," she said. "I think the options look pretty reasonable and pretty well-balanced, and I think we can all come to a general consensus."

If commissioners agree on a map, the commission will formally vote to approve it at the July 26 meeting, Lee said.

After that, the Cobb delegation will have to present the map to the state Legislature at its special session Aug. 15 for approval.

At that point, the delegation could make changes if they think it's necessary, said Lee.

If passed and then approved by the Justice Department, the new maps would go into effect for the November election.

"Once it passes the Legislature, the elections office will notify residents if their district changes," said Lee. "We'll probably do some education of our own."