By Suzi Parker

LITTLE ROCK, Ark., July 23 (Reuters) -- A campaign backed by two Walmart heirs seeking to allow retail alcohol sales in the Arkansas county that is home to the company's headquarters has gathered enough signatures to put the question before voters on Nov. 6, officials said on Monday.

Benton County Clerk Tena O'Brien said on Monday that her office had accepted 41,460 valid signatures -- 300 more than needed to secure a spot on the ballot. The campaign had submitted 54,150 signatures in total.

More than half of Arkansas's 75 counties are dry, meaning they have prohibitions on the sale of alcoholic drinks. Most dry counties are in the South, with some also scattered in the so-called "Rust Belt" of the Midwest and Northeast. In recent years, many dry counties have passed initiatives to allow alcohol sales either in restaurants, retail stores or both.

Walmart is among the businesses that sell beer and wine in stores in Arkansas's wet counties.

The Walmart heirs, Tom and Steuart Walton, were the largest donors to a campaign dubbed "Keep Dollars in Benton County." Together, the two spent $360,000 on the effort, according to a report filed with the Arkansas Ethics Commission. Steuart Walton is involved in Walmart's expansion efforts in Europe.

The two brothers, who are grandsons of Walmart founder Sam Walton, could not be reached for comment on Monday.

Lawyer Marshall Ney, who managed the campaign, said in a statement earlier this year that Benton County is a "growing and dynamic area" and his group felt strongly that "county voters of today deserve an opportunity to make their voices heard on this issue through the democratic process."

But Benton County church leaders and liquor store owners in adjacent counties are against the measure.

"The last thing we need is more alcohol because it affects our children and our safety," said Galen Tearcy, pastor of Radiant Life Church in Bentonville, the city where Walmart is based.

The last time the issue was on the ballot in Benton County was in 1944, when its population was 38,000. Now it is more than 220,000. The county has been dry since 1935.

A study by the Walton School of Business, which the Walton family endowed at the University of Arkansas, estimates the annual impact of retail alcohol sales in Benton County would be $33 million.

Restaurants sell alcohol in Benton County under private club permits, but residents have to go across county lines to buy alcohol in a liquor store. Throughout Arkansas, some cities are dry within wet counties, but a city cannot vote to go wet in a dry county.

Opponents of the Benton County proposed ballot measure have 10 days to challenge it in court. (Editing by Corrie MacLaggan, Alex Dobuzinskis and Eric Beech)