The Grand Army of the Republic Hall, also known as the General Frederick W. Lander Post No. 5, Grand Army of the Republic, is an historic building located at 58 Andrew Street in Lynn, Massachusetts, in the United States. The hall was built in 1885 by members of the Grand Army of the Republic as a meeting hall and memorial to the Union Army veterans of the Civil War. Of many such halls built in the country, the Lynn GAR Hall is the largest. Only 13 remain nationwide, and only this one in Massachusetts. On May 7, 1979, it was added to the National Register of Historic Places.