Question: Clark's Lookout State Park is located one mile north of what city that is the county seat of Beaverhead County, Montana?

Context paragraphs:
Clark Canyon Dam: Clark Canyon Dam is an earthfill dam located in Beaverhead County, Montana, about 20 miles (30 km) south of the county seat of Dillon.  The dam impounds the waters of the Beaverhead River, creating a body of water known as Clark Canyon Reservoir.  The structure was constructed in 1961-1964 by the United States Bureau of Reclamation, to hold water for downstream irrigation and for flood-control purposes.

Bannack, Montana: Bannack is a ghost town in Beaverhead County, Montana, United States, located on Grasshopper Creek, approximately 11 mi upstream from where Grasshopper Creek joins with the Beaverhead River south of Dillon.  Founded in 1862, the town contemporarily operates as a National Historic Landmark and is managed by the state of Montana as Bannack State Park.

Crestview (Capital MetroRail station): Crestview is a Capital MetroRail commuter rail station as well as a Capital MetroRapid premium bus station in Austin, Texas.  It is located at the edge of the Crestview neighborhood of North Austin, at the corner of Airport and North Lamar Boulevards.  The North Lamar Transit Center is located one mile north of the station, while the Highland Mall Transit Center (across from the Highland Station) is located one mile south.  There is no onsite parking at the Crestview station.  Riders need to park at the North Lamar Transit center and take buses 1 or 801 down to the train.

Clark's Lookout State Park: Clark's Lookout State Park is a Montana state park located one mile north of the community of Dillon.  The 8 acre park encompasses the hill that overlooks the Beaverhead River that William Clark climbed on August 13, 1805 during the Lewis and Clark Expedition.  The park offers picnicking and a chance to make the same climb that Clark made.

Cape Lookout State Park: Cape Lookout State Park is a state park on Cape Lookout in the U.S. state of Oregon.  It is located in Tillamook County, south of the city of Tillamook, on a sand spit between Netarts Bay and the Pacific Ocean.

Armstead, Montana: Armstead is a former community in Beaverhead County, Montana, United States, about 21 mi south of the county seat of Dillon.  It was named after miner Harry Armstead.  Armstead was located in a narrow valley of the Beaverhead River, near the mouth of Horse Prairie Creek.  The town was a station stop on the Union Pacific Railroad line from Idaho Falls, Idaho to Butte, Montana.  There was a post office in Armstead from 1907 to 1962.

Cape Lookout (Oregon): Cape Lookout is a sharp rocky promontory along the Pacific Ocean coast of northwestern Oregon in the United States.  It is located in southwestern Tillamook County, approximately 10 mi southwest of Tillamook, just south of Netarts Bay.  The promontory extends 1.5 mi perpendicular to the coast, and is approximately 0.5 mi wide at its base, tapering as it extends outward from the coast.  Cape Lookout State Park is located on the north side of the promontory, which is part of the Siuslaw National Forest.  Cape Lookout Road travels past the base of the cape.  Cape Lookout is a member of Tillamook's Three Capes Scenic Drive.

Point Lookout State Park: Point Lookout State Park is a Maryland state park occupying Point Lookout, the southernmost tip of a peninsula formed by the confluence of Chesapeake Bay and the Potomac River in St. Mary's County, Maryland.  The state park preserves the site of an American Civil War prisoner of war camp and the Point Lookout Light, which was built in 1830.  It is the southernmost spot on Maryland's western shore, the coastal region on the western side of the Chesapeake Bay.

Dillon, Montana: Dillon is a city in and the county seat of Beaverhead County, Montana, United States.  The population was 4,134 at the 2010 census.  The city was named for Union Pacific Railroad President Sidney Dillon.

Margarita Lookout: Margarita Lookout, also known as Santa Margarita Lookout, is a lookout point in the Santa Margarita Mountains, part of the larger Santa Ana Mountains in San Diego County, California.  The original fire lookout tower, built in 1935 by the CCC, was later replaced by a new lookout tower and cabin in 1965.  In 1986, the tower and cabin were both burned in a wildfire.  In 1988, the burnt tower was destroyed in a collision with a Marine Corps CH-46E helicopter.  The lookout tower was badly damaged as a result and was promptly removed.  Only a concrete foundation remains today, however the site is still accessible via trail (Margarita Road/Truck Trail).  The lookout is approximately one mile north of Margarita Peak, and is located in the Cleveland National Forest.

Supporting paragraphs: Clark's Lookout State Park Dillon, Montana
Answer: Dillon