Monocacy National Battlefield Monocacy National Battlefield is a unit of the National Park Service , the site of the Battle of Monocacy Junction in the American Civil War fought on July 9 , 1864 . The battlefield straddles the Monocacy River southwest of the city of Frederick , Maryland . The battle , labeled " The Battle That Saved Washington , " was one of the last the Confederates would carry out in Union territory . The two opposing leaders were General Jubal Early , fighting for the South , and General Lew Wallace , fighting for the North . Monacacy National Battlefield is located in the center of a region with a number of other Civil War battlefields and sites . It is located on Maryland State Highway 355 ( Urbana Road ) a few miles southeast of the city of Frederick . Nearby Interstate 70 leads westward to Antietam National Battlefield and U . S . Route 15 leads northward to the Gettysburg Battlefield . To the south on U . S . 15 is the battlefield of Balls Bluff . Monacacy National Battlefield is west of Baltimore and northwest of Washington D . C . . Much of the Monocacy battlefield remained in private hands for over 100 years after the Civil War . In 1928 , Glenn Worthington , the owner of a large portion of the northern segment of the battlefield , petitioned Congress to create a National Military Park at Monocacy . Though the bill passed in 1934 , the battlefield languished for nearly 50 years before Congress appropriated funds for land acquisition . Once funds were secured , of the battlefield were acquired in the late 1970s and turned over to the National Park Service for maintenance and interpretation . The historic Thomas Farm , scene of some of the most intense fighting , was acquired by the National Park Service in 2001 , and is currently subject to a life estate . Preservationists lost fights in the 1960s and 1980s when Interstate 270 was constructed and later widened , bisecting a portion of the battlefield . In the decades following the battle , a few veterans organizations placed commemorative markers to specific units on the battlefield , including the 14th New Jersey ( dedicated in 1907 ) , 87th Pennsylvania Infantry , and Vermont markers . In the years that have followed , other monuments have been added , including the Confederate Monument and Maryland Centennial Monument near the Best farm ( the site where Union soldiers discovered Robert E . Lee ' s lost Special Order 191 during the 1862 Maryland Campaign ) . The National Park Service has since added wayside interpretive markers throughout the park . The visitor center has been relocated from the historic Gambrill Mill to a new facility on the west side of the Monocacy River . It offers an electric map orientation program , an interactive computer program , interpretive displays , and artifacts of the battle . The visitor center is the starting point for a self - guided four - mile ( 6 km ) auto tour and 1 / 2 mile ( 800 m ) loop walking trail . National Park Service rangers and volunteers host battle walks , special programs , an auto tour and special events throughout the summer season . The interpretive Worthington Farm Trail , a pair of loops ( one nearly two miles ( 3 km ) long , the other 1 . 6 miles ( 2 km ) ) on the northern portion of the battlefield , allows the visitor to walk parts of the battlefield and explore the native flora of the region . The National Park Service has recently established a General Management Plan to further interpret the area and acquire additional land if funding can be secured .