Pretty much all of Kennecott comprises the mill town and there are dozens of old wood and log buildings that have been restored, stabilized or purposely left in a state of decrepitude. You're welcome to wander around the outside of the buildings at will, or you can join daily tours.
One of the most interesting ruins is the 14-story Concentration Mill & Leaching Plant , which used to process the copper ore through a multistage process. You can only enter the mill on a two-hour tour led by St Elias Alpine Guides , but this is highly recommended both for the stunning views from the top floors and the chance to get up close and personal with the hulking machinery. There are three tours daily.
