"I don't feel like we are protected," despite programs such as Rural Legacy and Program Open Space, Gale said.
The land is zoned agricultural so a special exception would be needed for a fast-food restaurant, officials said.
Washington County Commissioner Bert L. Iseminger, a member of the Washington County Planning Commission, said he was 99 percent sure the exception wouldn't have been granted if it were requested. The Board of Zoning Appeals hears requests for special exceptions.
The land owner could not be reached for comment.
Commissioners President Gregory I. Snook said the commissioners have no plans for the area to be commercially developed, nor do they want it to be.
Gale said he wants to avoid "the Gettysburg syndrome" of commercial development around Antietam National Battlefield.
To protect the battlefield, county zoning and planning officials need to talk about where the area is headed, he said.
Snook said the county is in the midst of a two-year process to gather public input and update its comprehensive plan.
"We don't have two years," said Town Councilman Ralph Hammond.
The county then will look at updating zoning regulations, Iseminger said.
Sharpsburg officials also want progress on a proposed heritage area to slow down so elected officials throughout Washington County understand what they're endorsing.
Sharpsburg refused to endorse plans for a Civil War Heritage Area that would include parts of Washington, Frederick and Carroll counties. Several other towns have endorsed the plan.
The recognition would make towns in the area eligible for tourism and financial benefits and the heritage area would be eligible for state grants, loans and income tax credits.
An up-to-date draft of the proposal has not been presented to the council, council members said.
Councilman Russell Weaver said restaurants don't locate in Sharpsburg because there isn't enough traffic. That could change if the heritage area is approved.
Planning Director Bob Arch is to discuss the heritage area at the council's regular meeting at 7:30 p.m. on Monday, Mayor George Kesler said.