To hike the loop, it’s best to get an early start and take Spiro uphill. It begins switchbacking immediately up a south-facing slope with some exposed patches so you’ll want to do it before temperatures rise midday. Though it forgoes any gentle warm-up, getting a lot of climbing out of the way early is an advantage during summer. The trail alternates between sunny ski runs and shady groves of whispering aspens and deep pines. From its intersection with Mid Mountain, turn right and head north, then take Armstrong Trail as it winds downhill.

Both of these trails are shared with bikers, but Armstrong only allows uphill bike traffic. This is another reason why it’s better to go up Spiro and down Armstrong, because on Spiro you’ll see the downhill riders coming. If you don’t mind backtracking, you might prefer to take Armstrong Trail both directions to avoid high-speed bike traffic.

Near the base, along Silver Star Drive, you can find the Spiro Tunnel, an old silver mine started in the late 1800s. Today it is gated and closed to public entry, but it makes an interesting historical aside to a day hiking Spiro Trail.

Sources: https://www.stayparkcity.com/blog/top-park-city-hikes/ http://www.parkcityreservations.com/blog/post/the-best-hiking-trails-in-park-city https://assets.vailresorts.com/-/media/park-city/files/18pcsummermap.ashx?la=en https://westernmininghistory.com/minedetail/10011488/