Shifts in population patterns during the past 10 years, dominated by flight from inner cities, have resulted in big population gains in Republican-held districts of the Ohio House and Senate, and big population losses in districts held by Democrats.

A JournalNews and Middletown Journal examination of U.S. Census data show the state’s 59 Republican House districts gained close to 420,000 people, while the 40 districts held by Democrats lost more than 238,000 people.

In the Senate, the examination revealed the 23 GOP-held districts gained more than 400,000 people while the 10 Democratic-held districts lost almost 220,000.

The shifts reflect the migration of urban residents — both black and white — to suburban and even previously rural areas. In addition to the social and economic implications, the population changes will result in dramatically different political boundaries, possibly cementing one-party control for the GOP until 2022.

Republicans hold all the cards. They control the Apportionment Board 4-1 and, if history is any guide, can be expected to draw districts that protect as many of their candidates as possible while squeezing Democrats.

“In the end, I think the GOP’s control of the Apportionment Board is the most important consequence of the 2010 elections,” said Mark Caleb Smith, director for the Center for Political Studies Cedarville University.

The board consists of Gov. John Kasich, Secretary of State Jon Husted and Auditor Dave Yost, all Republicans, and a legislator from each party. It must adopt a plan by Oct. 1 and publish it by Oct. 5. The new districts take effect in January 2013.

Political scientist John Green said Republicans can draw the map in ways that appear to strengthen GOP-held districts while pitting incumbents against each other in some Democratic-held districts.

The changes, however, might not be all bad for the Democrats, Green said.

“In the longer run, population shifts may not be as favorable to Republicans because voters may be more diverse in demographic terms,” said Green, director of the Bliss Institute of Applied Politics at the University of Akron. “For example, the shift of minorities and young people to the suburbs may make those districts more competitive.”

Whatever the ultimate results, the population shifts are dramatic in both House and Senate districts.

Ohio House

The eight fastest-growing House districts were all Republican, while the 20 biggest population losers were all Democratic.

Ohio’s overall population increased by 183,364, meaning each House district will gain about 1,850 people from the districts drawn a decade ago, while each Senate district picks up about 5,500. That means the big-gaining districts will shrink in area, while the population losers will expand. The GOP map-drawers will likely try to concentrate Democrats in as few districts as possible, thereby giving Republicans better odds at the rest.

Population shifts could significantly alter the political boundaries in Southwest Ohio. House District 67, held by State Rep. Peter Beck, R-Mason, gained 34,339 people, the third-largest gain of any district in Ohio. Right behind, with the fourth largest gain, was District 55, held by State Rep. Margaret Conditt, R-Liberty Twp., which increased by 24,284.

The district lines 53rd and 54th House districts, currently represented by Rep. Tim Derickson, R-Hanover Twp., and Rep. Courtney Combs, could get larger when the lines are redrawn. The 53rd district grew 6.3 percent and 54th district grew 3.6 percent, both a few thousand under the maximum threshold.

Butler County’s population is about 30,000 over, said Combs, but he hopes nothing changes despite the growth in the districts.

“My message to Secretary of State Husted was to, ‘Leave Butler County alone,’” he said.

But if anything does change, Combs said, part of West Chester Twp. could see a new state representative, likely from Hamilton County.

“That’s kind of the way I see it playing out,” Combs said.

Ohio Senate

In the Senate, the 14 fastest-growing districts were all Republican, while eight of the nine biggest losers were held by Democrats.

The third- and fifth-largest state Senate district gains were also in this region. District 7, held by State Sen. Shannon, R-Clearcreek Twp., gained 48,939 people, an increase of 14.8 percent, while District 4, held by State Sen. Bill Coley, R-Liberty Twp., gained 35,323 or 10.6 percent.

Coley said he’s like to see Butler County be represented by it’s current elected officials.

“Voters in Butler County have different sets of issues than voters in Hamilton, Warren and Preble counties,” he said.

District 7th, which encompasses all of Warren County and parts of western Hamilton County grew 14.8 percent in between census counts.

Migration of minorities

The role of minorities adds a twist to the population shifts. Historically, minorities — specifically African-Americans — have been strong supporters of Democrats. But as they spread out, it could be harder for Republican map-drawers to overwhelmingly “pack” Democratic districts with Democratic voters, leaving fewer of them to make other districts more competitive, said political scientist Herb Asher, professor emeritus at the Ohio State University.

In the Senate, Republican-held districts gained more than 318,000 minorities, while Democratic districts gained only about 44,000 minorities.

Still, minorities in the Republican districts amounted to 13.1 percent of the population in 2010, compared to 33.8 percent in the Democratic districts.

The redistricting ball is in the Republican court, but they still have to make choices, said Green.

“The Republicans will have to decide if they want more safe Republican districts — but also allowing for more safe Democratic districts — or if they want more districts that lean Republican and thus could be competitive,” Green said.

“It is a choice between maximizing security or maximizing the number of seats the GOP could win.”

Staff Writer Michael D. Pitman contributed to this report.