US 15 Business begins at a superstreet intersection with US 15 (Catoctin Mountain Highway) opposite county-maintained Old Frederick Road. Access to northbound US 15 requires following southbound US 15 to a median U-turn. The superstreet intersection replaced a standard highway junction in 2004. US 15 Business heads north as a two-lane road that immediately intersects the old alignment of US 15, Old Emmitsburg Road, and crosses Toms Creek. The business route passes the campuses of St. Joseph's College and the Mother Seton Shrine. St. Joseph's College is a defunct liberal arts college for women whose operations were absorbed by Mount St. Mary's University. The campus is now the National Emergency Training Center, a Federal Emergency Management Agency facility that is home of the National Fire Academy, United States Fire Administration, Emergency Management Institute, and the National Fallen Firefighters Memorial. The Seton Shrine comprises the Basilica of the National Shrine of St. Elizabeth Ann Seton and St. Joseph's Provincial House of the Daughters of Charity of Saint Vincent de Paul.