Milwaukee Road 261 is a class "S3" 4-8-4 "Northern" type steam locomotive built by the American Locomotive Company (ALCO) in Schenectady, New York in July, 1944 for the Milwaukee Road.

It was used for heavy mainline freight and passenger work until being retired by the railroad in 1956. Instead of being cut up for scrap, 261 was preserved and donated to the National Railroad Museum in Green Bay, Wisconsin in 1958. Today, the locomotive is owned, operated and maintained by Minneapolis-based nonprofit organization Friends of the 261 , which runs occasional and seasonal excursion trains using the locomotive. The steam engine, restored in 1993, has logged more than 25,000 miles (40,000 km) under its own power since that time.