Thomspon Falls Island, at the foot of Gallatin Street, is a day-use park that’s closed to automobiles. It’s full of bluffs and rocky rises and is a good place to hike around and watch the birds, including the ospreys nesting on the bridge.
The Old Jail Museum (109 S. Madison St., 406/827-4002, mid-May–Labor Day, Mon.–Fri. noon–4 p.m.) is indeed housed in the old jail, behind the police station.
East of Thomspon Falls [1], the KooKooSint Mountain Sheep Viewing Area is a roadside pullout with several informative signs. (KooKooSint is the name given to David Thompson by the local Indians. It means “Man Who Looks at Stars.”) Bighorn sheep were eaten by the Flathead Indians and by Thompson, who found them a welcome addition to his sparse winter diet.
You’re most likely to see sheep here in the spring, when they’re at lower elevations eating the new grass, or during late November or December, when they descend to feed in the valleys and mate. Open south-facing slopes provide a winter habitat. The lambs are born in early May on the high ridges, and the sheep summer in the mountains. Mountain sheep have spongy hooves with hard edges to lend traction and support, allowing them to traverse steep slopes easily and quickly.
Links:
[1] http://www.moon.com/destinations/montana/missoula-and-northwestern-montana/the-lower-clark-fork/thompson-falls