The Walton League will provide upkeep for the lodge at an estimated cost of $180,000 to $200,000 a year, and will sponsor conservation and education programs.
Griffin said the lease is the best way for the cash-strapped DNR to maintain the property.
The deal has been criticized by hunters and others who say the state shouldn't allow a private group to restrict access to state-owned property.
Jack Wetzel, of Funkstown, an opponent of the deal, said Wednesday he was saddened but not surprised. "The little guys lose again," he said.
"This has affected every taxpayer that wants to take a walk in the woods ... . It was a dirty, stinking, back-door deal," said Bob Harsh of Williamsport.
Harsh said what bothered him the most about the deal was that it was approved without a public hearing.
"It will be the good old boys club all over again," said Joe Dieterle, a Williamsport hunter.
Tim Stahl, owner of Keystone Sporting Goods in Hagerstown, said he would not mind the proposal if it were short-term, but does not believe that will be the case.
"I think all Marylanders should have the rights of access to the land," Stahl said.
Michael Nelson, a DNR assistant secretary, told board members the Woodmont property will be open to all hunters during the two-week firearms deer season, even though that falls during the six months of the Walton League's lease.
Griffin said objections to the plan were from a minority of hunters who opposed the agreement for philosophical reasons or because they misunderstood it.
He passed out copies of a letter supporting the agreement signed by Paul Wolber, president of the Washington County Federation of Sportsmen's Clubs.
Griffin said that for a fee, the public can have access to the lodge on certain dates within the six-month period, and that anyone who pays the membership fee may join the Izaak Walton chapter.
Nelson said the fee was around $10,000.
County Commissioners President Gregory I. Snook said the purchase and the lease ultimately would be for the good of the public.
"There was no access before and now they do have some access. It may not be as much as what they want," he said.
Snook said the situation could have been handled better by having more of a dialogue with the public.
Commissioners James R. Wade and John S. Shank have questioned the state's handling of the issue.
Wade said Wednesday that he was under the impression after meeting with Nelson Tuesday that additional time would be allowed for public comment. Wade said the lease "was obviously a back-room deal with a group of business people" and said other businesses and clubs should have had the opportunity to bid on the property.
"We'd be hung if we tried to do something like that," Wade said.
Woodmont was a private club for 125 years. Members such as Delaware industrialist Eugene DuPont invited such guests as President Grover Cleveland and Babe Ruth to hunt deer, turkey and pheasant.
The state purchased the property in 1995 for $3 million and immediately began negotiations with some former owners to help preserve it. That led to the formation of a new Izaak Walton chapter based in Baltimore.
The purchase was made with Program Open Space money, which is generated by the state real estate transfer tax.
The state will use the lodge the rest of the year for conferences, classes and other events.
The Associated Press contributed to this story.