Question: Where are the headquarters of the league the Denver Pioneers play in?

Context paragraphs:
2013–14 Denver Pioneers men's basketball team: The 2013–14 Denver Pioneers men's basketball team represented the University of Denver during the 2013–14 NCAA Division I men's basketball season.  The Pioneers, led by seventh year head coach Joe Scott, played their home games at Magness Arena and were first year members of The Summit League.  They finished the season 16–15, 8–6 in The Summit League play to finish in fourth place.  They advanced to the semifinals of The Summit League Tournament where they lost to North Dakota State.

2011–12 Denver Pioneers men's basketball team: The 2011–12 Denver Pioneers men's basketball team represented the University of Denver during the 2011–12 NCAA Division I men's basketball season.  The Pioneers, led by fifth year head coach Joe Scott, played their home games at Magness Arena and were members of the West Division of the Sun Belt Conference.  They finished the season 22–9, 11–5 in Sun Belt play to finish in second place in the West Division.  They lost in the semifinals of the Sun Belt Basketball Tournament to WKU.  Despite having 22 wins, the Pioneers did not accept an invitation to a post season tournament.

2014–15 Denver Pioneers men's basketball team: The 2014–15 Denver Pioneers men's basketball team represented the University of Denver during the 2014–15 NCAA Division I men's basketball season.  The Pioneers, led by eighth year head coach Joe Scott, played their home games at Magness Arena and were members of The Summit League.  They finished the season 12–18, 6–10 in Summit League play to finish in a tie for sixth place.  They lost in the quarterfinals of The Summit League Tournament to North Dakota State.

Denver Pioneers men's ice hockey: The Denver Pioneers men's ice hockey team is a National Collegiate Athletic Association (NCAA) Division I college ice hockey program that represents the University of Denver.  The Pioneers are a member of the National Collegiate Hockey Conference (NCHC).  They play at Magness Arena in Denver, Colorado.  The Pioneers are tied with North Dakota for second in all-time NCAA National Hockey Championships with eight (1958, 1960, 1961, 1968, 1969, 2004, 2005, 2017) trailing only Michigan with nine.  Since the creation of the Western Collegiate Hockey Association in 1959, the Pioneers have won 9 WCHA Regular Season Championships (now the recipients of the MacNaughton Cup) and 14 WCHA Playoff Championships (now the recipients of the Broadmoor Trophy).  About 75 Pioneers have gone on to play in the National Hockey League, including Keith Magnuson, Kevin Dineen, Matt Carle (2006 Hobey Baker Award winner) and Paul Stastny.

2015–16 Denver Pioneers women's basketball team: The 2015–16 Denver Pioneers women's basketball represent Denver University in the 2015–16 NCAA Division I women's basketball season.  The Pioneers, led fourth year head by Kerry Cremeans, play their home games at the Magness Arena and are members of The Summit League.

2015–16 Denver Pioneers men's basketball team: The 2015–16 Denver Pioneers men's basketball team represented the University of Denver during the 2015–16 NCAA Division I men's basketball season.  The Pioneers, led by ninth year head coach Joe Scott, played their home games at Magness Arena and were members of The Summit League.  They finished the season 16–15, 7–9 in Summit League play to finish in sixth place.  They defeated Nebraska–Omaha in the quarterfinals of The Summit League Tournament to advance to the semifinals where they lost to South Dakota State.

2016–17 Denver Pioneers men's basketball team: The 2016–17 Denver Pioneers men's basketball team represented the University of Denver during the 2016–17 NCAA Division I men's basketball season.  The Pioneers, led by first-year head coach Rodney Billups, played their home games at Magness Arena and were members of The Summit League.  They finished the season 16–14, 8–8 in Summit League play to finish in a three-way tie for fourth place.  They lost in the quarterfinals of the Summit League Tournament to South Dakota State.

Denver Pioneers men's basketball: The Denver Pioneers men's basketball team represents the University of Denver and competes in the NCAA Division I men's college basketball in Denver, Colorado.  They are coached by second year head coach Rodney Billups and are members of the Summit League.  They play their home games at Magness Arena.

Denver Pioneers: The Denver Pioneers are the sports teams of the University of Denver (DU).  They play in the National Collegiate Athletic Association (NCAA) Division I, Denver is a member of The Summit League for men's and women's basketball, swimming and diving, men's and women's soccer, tennis and golf for both men and women, plus women's volleyball.  Other DU teams play in various conferences in the sports that are not sponsored by The Summit.  The men's ice hockey team is a charter member of the National Collegiate Hockey Conference (NCHC), which formed in 2011 with play beginning in 2013.  The lacrosse teams for men and women are members of the Big East Conference; the men began Big East play in the 2013–14 school year (2014 season), while the women left the Mountain Pacific Sports Federation (MPSF) after the 2016 lacrosse season.  Men's and women's skiing compete in the Rocky Mountain Intercollegiate Ski Association, while the women's gymnastics team became an affiliate of the Big 12 Conference starting with the 2015–16 season.

Summit League: The Summit League, or The Summit, is an NCAA Division I intercollegiate athletic conference with its membership mostly located in the Midwestern United States from Indiana and Illinois on the East of the Mississippi River to the Dakotas and Nebraska on the West, with additional members in the Western state of Colorado and the Southern state of Oklahoma.  Originally dubbed the Association of Mid-Continent Universities in 1982, on June 1, 2007, the conference changed its name from the Mid-Continent Conference.  League headquarters are in Elmhurst, Illinois.

Supporting paragraphs: Denver Pioneers men's basketball Summit League
Answer: Elmhurst, Illinois