Question: Springfield, Missouri is known as the "birthplace" of which original highway in the US Highway System?

Context paragraphs:
U.S. Route 41 Business (Marquette, Michigan): Business US Highway 41 (Bus.  US 41) was a state trunkline highway that served as a business loop off US 41 and M-28 in Marquette, Michigan, along Washington and Front streets.  The streets serve the downtown area of Marquette and are bordered by several commercial properties and businesses.  Those two streets originate with the early founding of the city in the middle of the 19th century.  Jurisdiction over them was transferred to the city as part of a highway swap that resulted in the decommissioning of the trunkline in 2005.  It was also previously co-designated Bus.  M-28, mirroring the Bus.  US 41/Bus.  M-28 designation previously used along Bus.  M-28 in Ishpeming and Negaunee.  Washington and Front streets had been a part of the state highway system since the 1910s, and a part of the United States Numbered Highway System since 1926.  The business loop designation dates back to the 1960s and was removed in 2005.

Springfield, Missouri: Springfield is the third-largest city in the state of Missouri and the county seat of Greene County.  As of the 2010 census, its population was 159,498.  As of 2016, the Census Bureau estimated its population at 167,319.  It is one of the two principal cities of the Springfield-Branson Metropolitan Area, which has a population of 541,991 and includes the counties of Christian, Dallas, Greene, Polk, Webster, Stone and Taney.  Springfield's nickname is "Queen City of the Ozarks" and it is known as the "Birthplace of Route 66".  It is home to several universities, including Missouri State University, Drury University, and Evangel University.

U.S. Route 33 in Michigan: US Highway 33 (US 33) is a part of the United States Numbered Highway System that was once located in Berrien County, Michigan.  At the time it was removed from the state, it was only about 2.8 mi long running north from the Indiana state line to an intersection with US 12 south of Niles.  The highway was not originally part of the US Highway System in the state; it was added in 1937 as a second designation for part of US 31 between the state line and St. Joseph.  It was later extended further north to the community of Lake Michigan Beach.  This extension became the only section of US 33 that was routed independent of another highway until it was truncated to Niles.  In 1997, US 33 was officially removed from the state.

M-86 (Michigan highway): M-86 is an east–west state trunkline highway in the US state of Michigan in the southern portion of the Lower Peninsula.  The highway starts at Business US Highway 131 (Bus.  US 131) and M-60 in Three Rivers and ends at US Highway 12 (US 12) near Coldwater.  In between, it crosses farm country and runs along a section of the Prairie River.  Following a highway originally numbered M-7, the roadway was renumbered M-86 in 1940.  It has been a part of the state highway system at least since 1927.  Two other roadways carried the M-86 designation in the 1920s.  Two bridges along the road are eligible for inclusion on the National Register of Historic Places (NRHP).

U.S. Route 2 in Michigan: US Highway 2 (US 2) is a component of the United States Numbered Highway System that connects Everett, Washington, to the Upper Peninsula (UP) of the US state of Michigan, with a separate segment that runs from Rouses Point, New York, to Houlton, Maine.  In Michigan, the highway runs through the UP in two segments as a part of the state trunkline highway system, entering the state at Ironwood and ending at St. Ignace; in between, US 2 briefly traverses the state of Wisconsin.  As one of the major transportation arteries in the UP, US 2 is a major conduit for traffic through the state and neighboring northern Midwest states.  Two sections of the roadway are included as part of the Great Lakes Circle Tours, and other segments are listed as state-designated Pure Michigan Byways.  There are several memorial highway designations and historic bridges along US 2 that date to the 1910s and 1920s.  The highway runs through rural sections of the UP, passing through two national and two state forests in the process.

U.S. Route 27 in Indiana: US Highway 27 (US 27) is a part of the United States Numbered Highway System that runs from Miami, Florida, to Fort Wayne in the US state of Indiana.  In Indiana, it is a State Road that enters the state in College Corner, Ohio, and West College Corner, Indiana.  The 117.78 mi of US 27 that lie within Indiana serve as a major conduit.  Most of the highway is listed on the National Highway System.  Various sections are rural two-lane highway, urbanized four-lane divided highway.  The northernmost community along the highway is Fort Wayne in the northeast part of the state.  The highway ends at an interchange with Interstate 69 (I–69) north of downtown Fort Wayne after serving the east central and northeast regions of Indiana.

Arkansas Highway 5: Highway 5 (AR 5, Ark. 5, and Hwy.  5) is a designation for three state highways in Arkansas.  The southern segment of 44.99 mi runs from Highway 7 in Hot Springs north to US Highway 70 (US 70) in Little Rock.  A northern segment of 146.63 mi begins at US Highway 67/US Highway 167 in Cabot and runs north to Missouri Route 5, including a lengthy overlap with Highway 25 between Heber Springs and Wolf Bayou.  A portion of Highway 5 is designated as part of the Sylamore Scenic Byway.

U.S. Route 66: U.S. Route 66 (US 66 or Route 66), also known as the Will Rogers Highway, the Main Street of America or the Mother Road, was one of the original highways within the U.S. Highway System.  US 66 was established on November 11, 1926, with road signs erected the following year.  The highway, which became one of the most famous roads in the United States, originally ran from Chicago, Illinois, through Missouri, Kansas, Oklahoma, Texas, New Mexico, and Arizona before ending at Santa Monica, California, covering a total of 2448 mi .  It was recognized in popular culture by both the hit song "(Get Your Kicks on) Route 66" and the "Route 66" television show in the 1960s.

U.S. Route 41 in Michigan: US Highway 41 (US 41) is a part of the United States Numbered Highway System that runs from Miami, Florida, to the Upper Peninsula of the US state of Michigan.  In Michigan, it is a state trunkline highway that enters the state via the Interstate Bridge between Marinette, Wisconsin, and Menominee, Michigan.  The 278.769 mi of US 41 that lie within Michigan serve as a major conduit.  Most of the highway is listed on the National Highway System.  Various sections are rural two-lane highway, urbanized four-lane divided expressway and the Copper Country Trail National Scenic Byway.  The northernmost community along the highway is Copper Harbor at the tip of the Keweenaw Peninsula.  The trunkline ends at a cul-de-sac east of Fort Wilkins State Park after serving the Central Upper Peninsula and Copper Country regions of Michigan.

U.S. Route 30 in Indiana: U.S. Route 30 (US 30) is a road in the United States Numbered Highway System that runs from Astoria, Oregon to Atlantic City, New Jersey.  In Indiana, the route runs from the Illinois state line at Dyer to the Ohio state line east of Fort Wayne and New Haven.  The 155.96 mi of US 30 that lie within Indiana serve as a major conduit.  The entire length of U.S. Route 30 in Indiana is included in the National Highway System (NHS).  The highway includes four-lane, rural sections, an urbanized, four-lane divided expressway, and several high-traffic, six-lane areas.  First designated as a US Highway in 1926, US 30 replaced the original State Road 2 (SR 2) and SR 44 designation of the highway which dated back to the formation of the Indiana State Road system.  A section of the highway originally served as part of the Lincoln Highway.  Realignment and construction projects have expanded the highway to four lanes across the state.  There are over 40 traffic signals between I-65 at Merrillville and I-69 at Fort Wayne.

Supporting paragraphs: Springfield, Missouri U.S. Route 66
Answer: U.S. Route 66