Kroger may still be king when it comes to the retail grocery business in Ohio, but the Cincinnati-based company is facing some stiff — and diverse — competition.

“Giant Eagle has been very aggressive,” said Nate Filler, president and CEO of the Ohio Grocers Association, Columbus. “They’re putting in more of their Market District stores.”

Pittsburgh-based Giant Eagle started opening its Market District concepts in Ohio about four years ago, Filler said. The company, according to its website, now has three Market Districts in the Cleveland area, two in Columbus and one in Dublin. Another Market District is expected to open in the state in 2015, according to the company’s website.

Filler said Market Districts have all the things a consumer would expect at a typical Giant Eagle store but also feature expanded wine and cheese offerings, more prepared foods and cooking lessons.

“The theme is slow, steady growth,” Filler said. “There’s a lot of competition for customers’ dollars.”

According to 2012 data, Kroger had a 40.1% market share in a 14-county area around its Cincinnati headquarters, compared to 19.1% for Walmart. Meijer was a distant third at 10.5%.

Another company being aggressive — but using a vastly different approach than Giant Eagle — is Aldi, the discount retailer.

“They’ve been around awhile, but now they are opening stores in locations you wouldn’t have expected — suburban neighborhoods and affluent neighborhoods,” Filler said. “And they’re getting a great response.”

The national chains aren’t alone. Filler said regional chains like Lucky’s Market, Boulder, Colo., and Fresh Thyme Farmers Market also are opening new stores in the state. Lucky’s has one store in Columbus, while Fresh Thyme has opened its first two Ohio stores this year — in Columbus and Cincinnati — and has plans to open a third in November.

So where does that leave small, independent retailers?

Jeff Heinen of Warrensville Heights, Ohio-based Heinen’s said small retail companies have to do something to differentiate themselves from the abundant competition.

“Everybody has to pick what they think is their niche in the market,” said Heinen, whose company has 21 stores in Ohio and Illinois. “Sometimes it works, and sometimes it doesn’t work so well. Grocers have always felt the market is ‘over-stored,’ and that’s a trend that has continued.”

Filler, whose association represents not only the giants like Giant Eagle but also hundreds of small grocers with one or two locations, said independent retailers can find that niche by ramping up specialty areas.

“A fresh and bountiful produce department is important, as are high-end meat departments and a scratch bakery,” he said.

According to the National Grocers Association, Ohio’s 821 independent grocery stores earn more than $5 billion in annual sales.

“We still do have a few great independents that do well,” said Tom Sirna, president of Ravenna-based Sirna and Sons Produce. “And we have seen a few actually expand into downtown Cleveland, which has been revitalized with people moving back down to live.”

Overall, Filler said Ohio retailers have enjoyed a strong summer and fall.

“Stores have been on a slow, steady growth trend,” he said. “We had a harsh winter. That was good initially because people went to the stores to stock up for winter, but we had a long lull after that. It really turned around in the summer. Sales have picked up.”