Question:  The Robyville Bridge carries Covered Bridge Road across a tributary of what river?
Context: The Northfield Falls Covered Bridge, also called the Station Covered Bridge, is a wooden covered bridge that carries Cox Brook Road across the Dog River in Northfield, Vermont.  Built in 1872, this Town lattice truss bridge is one of five surviving covered bridges in the town, and one of two that are visible from each other (the other is the Lower Cox Brook Covered Bridge).  It was listed on the National Register of Historic Places in 1974. Kenduskeag Stream is a 36.2 mi stream in the U.S. state of Maine.  It is a tributary of the Penobscot River.  The stream rises at the outlet of Garland Pond in the town of Garland, and flows southeast through Corinth, Kenduskeag, and Glenburn, before it reaches the city of Bangor.  Passing through downtown Bangor, the stream drops 100 ft in 2 mi , flowing into the Penobscot between the two downtown bridges across the larger river. The Kidder Covered Bridge carries Kidder Hill Road across the South Branch Saxtons River, just south of the village center of Grafton, Vermont.  The bridge was built about 1870, and is Grafton's last surviving 19th-century covered bridge.  It is the shortest historic covered bridge in Windham County, and was listed on the National Register of Historic Places in 1973. The Grist Mill Covered Bridge, also known as the Scott Covered Bridge, the Bryant Covered Bridge, and the Canyon Covered Bridge, is a covered bridge that carries Canyon Road across the Brewster River, off Vermont Route 108 in Cambridge, Vermont.  Built in the 19th century, it is one of a small number of surviving Burr arch truss bridges in the state, and is one of three left in Cambridge.  It was listed on the National Register of Historic Places in 1974. The Gorham Covered Bridge carries Gorham Bridge Road across Otter Creek in a rural area of Pittsford and Proctor, Vermont.  It is a Town lattice truss bridge, built in 1841 by Abraham Owen and Nicholas M. Powers, the latter in the early stages of his career as a well-known bridgewright.  The bridge was listed on the National Register of Historic Places in 1974. The Robyville Bridge is a historic covered bridge in Corinth, Maine.  Built in 1876, this Howe truss bridge is one of the state's few surviving 19th-century covered bridges.  It carries Covered Bridge Road across Kenduskeag Stream in the southern part of the rural community.  It was listed on the National Register of Historic Places in 1970. Fallasburg Bridge (alternatively Fallassburgh Bridge) is a 100 ft span Brown truss covered bridge, erected in 1871 in Vergennes Township, Michigan, United States, 5 mi north of Lowell on the Flat River.  Carrying Covered Bridge Road across the Flat, it is located in the Fallasburg Historical District south of Whites Bridge and Smyrna.  It is listed on the National Register of Historic Places, and along with Whites Bridge, Langley Covered Bridge, and Zehnder's Holz Brucke, is one of only four Michigan covered bridges open to vehicle traffic. The Halpin Covered Bridge, also called the High Covered Bridge, is a wooden covered bridge carrying Halpin Bridge Road across the Muddy Branch of the New Haven River in Middlebury, Vermont.  It was listed on the National Register of Historic Places in 1974. The Chamberlin (or Chamberlain) Mill Covered Bridge, also called Chamberlin Covered Bridge or Whitcomb Covered Bridge, is a historic covered bridge that carries Chamberlain Bridge Road across the South Wheelock Branch of the Passumpsic River in Lyndon, Vermont.  Built in 1881, it is one of five similar area bridges.  It was listed on the National Register of Historic Places in 1974. The Lovejoy Bridge is a historic covered bridge in South Andover, Maine.  It is a Paddleford truss bridge, which carries Covered Bridge Road over the Ellis River, about 9 mi north of US Route 2.  Built in 1868, it is one of a small number of 19th-century covered bridges remaining in the state, and it is the state's shortest covered bridge.  It was listed on the National Register of Historic Places in 1970.
Answer: Penobscot River