Question: Which Montana tributary was Emmet Sullivan born in?

Context paragraphs:
Carp Lake River: The Carp Lake River is a 10.5 mi river in Emmet County, Michigan, in the United States.  It is a tributary of Lake Michigan, joining it 5 mi west of the Straits of Mackinac.  It is fed by Lake Paradise.

Dinosaur Park: Dinosaur Park is a tourist attraction in Rapid City, South Dakota, United States.  Dedicated on May 22, 1936, it contains seven dinosaur sculptures on a hill overlooking the city, created to capitalize on the tourists coming to the Black Hills to see Mount Rushmore.  Constructed by the city of Rapid City and the Works Progress Administration, WPA Project #960's dinosaurs were designed by Emmet Sullivan.  Sullivan also designed the "Apatosaurus" (formerly "Brontosaurus") at Wall Drug nearby in Wall, South Dakota, the Christ of the Ozarks statue in Eureka Springs, Arkansas, and the dinosaurs at the now closed Dinosaur World in Beaver, Arkansas.

Emmet Sullivan: Emmet Sullivan, (May 27, 1887 – November 3, 1970) was an American sculptor.  He was born in Powder River, Montana, and worked on Mount Rushmore, and later created the five dinosaurs in Dinosaur Park in Rapid City, South Dakota in 1934, his first large scale project.  His other dinosaur creations were the Apatosaurus at Wall Drug in Wall, South Dakota in the late 1960s, and the many dinosaurs of Dinosaur World in Beaver, Arkansas.  In 1966 Sullivan sculpted the 20 meter tall Christ of the Ozarks statue in Eureka Springs, Arkansas.

Jane Emmet de Glehn: Jane Erin Emmet de Glehn (born Jane Erin Emmet in 1873; died 20 February 1961) was an American figure and portrait painter.

Powder River (Wyoming and Montana): Powder River is a tributary of the Yellowstone River, approximately 375 mi long in northeastern Wyoming and southeastern Montana in the United States.  It drains an area historically known as the Powder River Country on the high plains east of the Bighorn Mountains.

Sullivan Branch: Sullivan Branch (also known as Sullivan Run or the Sullivan Branch of East Branch Fishing Creek) is a tributary of East Branch Fishing Creek in Sullivan County, Pennsylvania, in the United States.  It is approximately 3.3 mi long and flows through Davidson Township.

Jim Sullivan (writer): James Sullivan born 1978 is an English television screenwriter.  He is a son of John Sullivan, writer of a number of British sitcoms, but most notably "Only Fools and Horses", its spin-off "The Green Green Grass" and prequel "Rock & Chips".

Painter Run: Painter Run (also known as Painter's Run) is a tributary of West Branch Fishing Creek in Sullivan County, Pennsylvania, in the United States.  It is approximately 4.5 mi long and flows through Davidson Township.  The watershed of the stream has an area of 5.20 sqmi .  It has one named tributary, which is known as Oxhorn Run and one unnamed tributary.  Painter Run is slightly acidic, with pH values ranging from 5.99 to 6.88.  The stream is in a narrow valley with several ridges nearby.  Sandstone of the Pocono Formation occurs near it.  At least two bridges have been constructed over the stream.  Its unnamed tributary is considered to be Class A Wild Trout Waters.

Bob McGrath: Robert Emmet "Bob" McGrath (born June 13, 1932) is an American singer and actor best known for playing original human character Bob Johnson on the long-running educational television series, "Sesame Street".  He was born in Ottawa, Illinois.  McGrath was named for Irish patriot Robert Emmet.

Bear River (Michigan): Bear River is a small clear slow-moving river in the U.S. state of Michigan.  14.7 mi long, it is the largest tributary of Little Traverse Bay in the northwest of the lower peninsula.  Traverse Bay is on Lake Michigan.  The river is formed as the outflow of Walloon Lake on the boundary between Charlevoix County and Emmet County, draining from the southeast end of the lake at near the community of Walloon Lake in Melrose Township.  M-75 has its northern terminus in a junction with US 131 nearby.

Supporting paragraphs: Emmet Sullivan Powder River (Wyoming and Montana)
Answer: Powder River