Gen. Robert E. Lee’s headquarters during the Battle of Gettysburg, a small stone house on Seminary Ridge, has never risen to the high level of interest and protection that the battlefield and other related buildings have been given. Tuesday marks the 151st anniversary of the Gettysburg battle and the Civil War Trust and other preservation and government groups will use that anniversary to announce a national campaign at 10 a.m. at the house to raise $5.5 million to acquire the four-acre site and several buildings.

According to a Civil War Trust press release, much of that money has already been raised from private donors and the trust has applied for a Civil War Land Acquisition Grant  of up to $1.5 million from the American Battlefield Protection Program. If that occurs, the trust will then have to raise the remaining $1.1 million by the end of this year.

The two-story house was built in 1834 and at the time of the battle was occupied on one side by Mrs. Mary Thompson, know locally as the Widow Thompson. The other side of the duplex was empty and it was here that Lee made his headquarters. According to an online history of the house, Lee’s staff chose the building because of its thick walls and its proximity to the center of the Confederate lines.

Since 1922, the house has operated as the private Lee Museum, offering tours of the building and a display of artifacts from the battlefield. Nearby is a modern building housing a 48-room Quality Inn and a restaurant. The hotel, restaurant, museum and a brewing company also on the site will continue to operate until the sale is final sometime in early 2015, according to Civil War Trust officials.