Applications for three or four land acquisition requests were turned in last summer to Interior Secretary Bruce Babbitt after Sen. Robert Torricelli, D-N.J., toured the battlefield, Howard said.
Antietam officials asked for about $2.5 million to buy three or four properties within the boundary of the battlefield, Howard said.
All but one of the properties, all agricultural and considered to be a historical part of the battlefield, are for sale, he said.
"Most landowners at one time have wanted to sell, but we've never had enough money to buy," Howard said.
Last August, Howard listed the battlefield's top purchase priority as a 160-acre farm owned by Howard Miller. The farm is in the center of the battlefield along Bloody Lane.
Development isn't as much of a threat to Antietam as it is to other battlefields, said Dennis E. Frye, president of the Association for the Preservation of Civil War Sites.
Acquiring the private property would increase the amount of land accessible to battlefield visitors, he said.
"The ultimate goal is to complete the acquisition within the battlefield boundaries ... There are very few that can claim absolute acquisition," Frye said.
Torricelli asked Babbitt to include Antietam, Gettysburg and a battlefield in Fredericksburg-Spottsylvania in Virginia on a priority acquisition list. The request was made in a letter signed by Sen. Paul Sarbanes, D-Md., and two other senators.
Torricelli said a total of 3,130 acres at the three battlefields needs to be purchased.
Those battlefields, Monocacy, and Stones River in Tennessee are listed on the spending plan.
Last year, Congress set aside $700 million for land purchases in the budget. The money was from the Land and Water Conservation Fund, made up of royalties from oil and gas leases.
Half of the $700 million will be used to buy the New World Gold Mine near the border of Yellowstone National Park, and to purchase a rare private grove of old-growth redwood trees in the Headwaters forest in California.