The city of Austin has always had the Colorado River run through it. However, it wasn’t until the 1957 Broadway musical The Music Man (with its “River City” based on Mason City, Iowa) that the term “River City” became widely known and used by American cities. Austin acquired the ‘River City” nickname by at least 1973, as evidenced by a print citation for the “River City Inn.” Several Austin businesses still use the ‘River City” nickname, although the nickname hasn’t been officially promoted by Austin tourist materials.
     
San Antonio (TX) has also used the “River City” nickname.
     
   
Wikipedia: Austin, Texas
Austin is the capital of the U.S. state of Texas and the county seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 15th-largest in the United States. It was the third-fastest-growing large city in the nation from 2000 to 2006] According to the 2009 U.S. Census estimate, Austin had a population of 757,688. The city is the cultural and economic center of the Austin–Round Rock Metropolitan Area, with a population of 1,652,602 as of the July 2008 U.S. Census estimate—making it the 36th-largest- and 2nd-fastest-growing metropolitan area in the nation.
 
The area was settled in the 1830s on the banks of the Colorado River by pioneers who named the village Waterloo. In 1839, Waterloo was chosen to become the capital of the newly independent Republic of Texas. The city was renamed after Stephen F. Austin, known as the father of Texas. The city grew throughout the 19th century and became a center for government and education with the construction of the Texas State Capitol and the University of Texas. After a lull in growth from the Great Depression, Austin resumed its development into a major city and emerged as a center for technology and business. Today, Austin is home to many companies, high-tech and otherwise, including three Fortune 500 corporations, Dell, Whole Foods Market, and Freescale Semiconductor.
 
Austin was selected as the No. 2 Best Big City in “Best Places to Live” by Money magazine in 2006, and No. 3 in 2009, also the “Greenest City in America” by MSN. According to CNN Headline News and Travel & Leisure magazine, Austin ranks No. 2 on the list of cities with the best people, referring to the personalities and attributes of the citizens. Austin was also voted America’s #1 College Town by the Travel Channel. Austin was ranked the fifth-safest city in part because there are fewer than 3 murders per 100,000 people annually.

Residents of Austin are known as “Austinites” and include a diverse mix of university professors, students, politicians, musicians, state employees, high-tech workers, blue-collar workers, and white-collar workers. The main campus of the University of Texas is located in Austin. The city is home to enough large sites of major technology corporations to have earned it the nickname “Silicon Hills.” Austin’s official slogan promotes the city as “The Live Music Capital of the World,” a reference to its status as home to many musicians and music venues. In recent years, many Austinites have also adopted the unofficial slogan “Keep Austin Weird”; this refers partly to the eclectic and progressive lifestyle of many Austin residents but is also the slogan for a campaign to preserve smaller local businesses and resist excessive commercialization
 
Wikipedia: The Music Man
The Music Man is a musical with book, music, and lyrics by Meredith Willson. The show is based on a story by Willson and Franklin Lacey. In 1957, the show became a hit on Broadway and spawned revivals and a popular film. It is still frequently produced by both professional and amateur theater companies.
   
Background
Meredith Willson was inspired by his boyhood in Mason City, Iowa, in writing and composing his first musical, The Music Man. He first approached producers Cy Feuer and Ernest Martin for a television special, and then MGM producer Jesse L. Lasky. After these and other unsuccessful attempts, Willson invited Franklin Lacey to help him edit and simplify the libretto. At this time, Willson considered eliminating a long piece of dialogue about the serious trouble facing River City parents. Willson realized it sounded like a lyric, and transformed it into the now-famous song, “Ya Got Trouble”.
   
Google.com
Local business results for “river city” near Austin, TX
A. River City Mechanical - maps.google.com - (512) 385-4961
B. River City Aquatics - http://www.rivercityaquatics.com - (512) 219-7200
C. River City Hose and Supply - http://www.rivercityhoseandsupply.com - (512) 506-8450
D. River City Donuts - maps.google.com - (512) 445-5779
E. River City Youth Foundation Ph - http://www.rivercityyouth.org - (512) 440-1111
F. River City Tattoo - maps.google.com - (512) 476-8282
G. River City Dental - http://www.benchmarkdental.com - (512) 326-2066
H. River City Bingo - maps.google.com - (512) 339-0584
I. River City Graphic Supply - http://www.rivercitygraphicsupply.com - (512) 454-0505
J. River City Rangers Soccer Club - http://www.rivercityrangers.org - (512) 832-1499
   
Google Books
March 1973, Texas Monthly, pg. 24:
River City Inn, 304 E. 6th St. (472-6741).
(Austin—ed.)
 
Google News Archive
18 July 1974, Hays County (TX) Citizen, “Capital Talk” by Winston Bode, pg. 7, col. 3:
Is River City becoming Sound City? The sophisticated equipment at the Odyssy Sound, Ltd. studio 308 West 6th, Austin is some days kept busy around the clock by recording groups.
   
30 May 1990, Austin (TX) American-Statesman, “River City Currents,” pg. D1:   
Welcome to River City Currents: a periodic compilation of cutting-edge trends, news you can use and just plain interesting stuff. Our aim is to inform and entertain, to start your day off with a smile. And if you’re a seasoned trend-spotter or you know a good joke, when you hear one send it along.
 
Google Books
Day Trips from Austin, 5th By Paris Permenter, John Bigley
Day trips from Austin:
Getaway ideas for the local traveler
Fifth Edition
By Paris Permenter, Shifra Stein and John Bigley
Guilford, CT: Insiders’ Guide
2008.
Pg. 104:
Many towns boast nicknames, from Austin’s “River City” to San Antonio’s “Alamo City.”
     
Austin (TX) American-Statesman
Austin as ‘Open City’ 2
By Michael Barnes | Monday, April 6, 2009, 01:49 PM
Austin has suffered through a history of cursed slogans.
(...)
Through most of the 20th Century, Austin made do with “River City,” a rallying cry it shared with 5,763 other North American burgs, including the fictional location of “The Music Man.”
 
The name survives through businesses and teams such as River City Aquatics, River City Rangers Soccer Club and River City Donuts.
 
Really? River City was the best our fore-parents could do? Well, Houston was known as “Bayou City” before it became “Space City.” Not much more concise.