Today the race follows much of the primary route of the Iditarod National Historic Trail, with a segment alternating north or south, depending on the year. (These segments are also part of the Iditarod National Historic Trail). Every odd year (i.e., 2011), the race travels the south route from Ophir to Kaltag through the ghost town of Iditarod. On even years, the race travels north from Ophir through Ruby and Galena to Kaltag. The 1925 Serum Run followed of trail (now designated as the Iditarod National Historic Trail system) between Ruby and Nome.