“McKinneyite” is the name of an inhabitant of McKinney, Texas. The name “McKinneyite” has been cited in print since at least 1886.
 
 
Wikipedia: McKinney, Texas
McKinney is a city in and the county seat of Collin County, Texas, United States, and the second in population to Plano. According to the U.S. Census Bureau, the city’s 2010 population was 131,117. The Census Bureau listed McKinney as the nation’s fastest growing city from 2000 to 2003 and again in 2006, among cities with more than 50,000 people. In 2007 it was ranked second-fastest growing among cities with more than 100,000 people and in 2008 as third-fastest. In July 2010, McKinney was ranked 5th place in CNN’s Money Magazine‘s list of best places to live in the United States. Also, McKinney is the only City in Texas that made the top ten. McKinney is one of several fast-growing communities on the northeastern edge of the Dallas-Fort Worth Metroplex. Both the city and county are named after Collin McKinney, a signer of the Texas Declaration of Independence, and a congressman for the Red River district of the Republic of Texas.
   
19 September 1886, Dallas (TX) Morning News, “McKinney Matters,” pg. 7, col. 6:
The theatrical season was inaugurated at Heard’s Opera-house last night. The opera-house has been refitted and McKinneyites count on a gay season.
 
6 April 1891, Dallas (TX) Morning News, pg. 1, col. 6:
McKinneyites Had a Big Time.
McKINNEY, Tex., April 5.—Many democrats were in a quandary whether to go down to the Cole demonstration or not.
 
25 July 1903, Dallas (TX) Morning News, pg. 9, col. 3:
McKinneyites Draw Territory Lots.
 
Google Books
The Cotton Queen
By Pamela Morsi
Don Mills, ONT: Harlequin Books
2006
Pg. 308:
“I am ordinary Stanley Kuhl who’d like to take an attractive woman to dinner without becoming breaking news for bored McKinneyites.”
   
Star Local News (TX)
McKinney remembers: Residents come together for Pecan Grove ceremony
By Paul Gosling, McKinney Courier-Gazette
Published: Tuesday, May 27, 2008 9:25 AM CDT
“America’s important,” said U.S. Rep. Sam Johnson, R, Plano. “If we value our freedom, we ought to value those who gave their lives to fight for it.”
 
Those words and the sentiments behind them drew Johnson and an estimated 1,000 other Collin County residents to the 24th Pecan Grove Cemetery Memorial Day Program Monday.
 
Attendees at the ceremony were welcomed by the President of Pecan Grove Ceremony Harry McKillop. “I have great personal pride in welcoming all the ‘McKinneyites’ and neighbors attending the ceremony,” he said.