US 15 continues north concurrent with US 40 along the six-lane Frederick Freeway. US 40 exits the freeway at a partial cloverleaf interchange with Patrick Street, which heads east toward downtown Frederick and west through the heavily commercialized Golden Mile. US 15 crosses Carroll Creek and continues north with four lanes through folded diamond interchanges with Rosemont Avenue, 7th Street, and Motter Avenue. All three streets provide access to Fort Detrick, home of the United States Army Medical Research Institute of Infectious Diseases. In addition, Rosemont Avenue leads to Hood College and Motter Avenue connects the freeway with Frederick Community College. The route comes to partial interchange with the western terminus of MD 26 (Liberty Road) before the Frederick Freeway ends at a diamond interchange with Monocacy Boulevard/Christophers Crossing.