Question: Where was John Callahan, creator of John Callahan's Quads, from? 

Context paragraphs:
John Callahan (cartoonist): John Michael Callahan (February 5, 1951 – July 24, 2010) was a cartoonist, artist, and musician in Portland, Oregon, noted for dealing with macabre subjects and physical disabilities.

Don't Worry, He Won't Get Far on Foot: Don’t Worry, He Won’t Get Far on Foot is an upcoming American drama film, written and directed by Gus Van Sant, based upon the memoir of the same name by John Callahan.  It stars Joaquin Phoenix, Rooney Mara, Jonah Hill, Jack Black and Mark Webber.

John Callahan (outlaw): John Callahan (1866 – June 8, 1936) was an American outlaw and bank robber during the closing days of the Old West.  He eventually became the leading underworld figure in Wichita, Kansas during Prohibition, specifically becoming involved in bootlegging and narcotics.  He was also considered one of the top fences in the Midwestern United States buying negotiable bonds and laundering money.

John Callahan House: John Callahan House, known previously as Pinkney-Callahan House when it was located on St. John Street, is a historic home in Annapolis, Maryland, United States.  The brick home was constructed by John Callahan (c. 1754-1803), a prominent and wealthy Annapolitan who served as the Register of the Western Shore Land Office between 1778 and 1803, around 1785-90.  It has been moved twice in efforts to prevent its demolition.  In 1900-01, the house was relocated to St. John’s Street and then to its present site on Conduit Street in 1972.  The home features an unusual gable-end principal façade and a largely intact Georgian/Federal interior finishes.  It once served as St. John's College Infirmary.

John Callahan (wrestler): John Callahan (born 1964) is best known as a former professional wrestler in the World Wrestling Federation (WWF) and later, as the Circulation Director of the Milford Daily News in Milford, Massachusetts.  He held the New England Heavyweight title twice, from June 1994 to November 1995, and the New England Tag Team title (along with fellow wrestler Big City Mike) from November 1993 to July 1995.

Dennis Callahan: Dennis Michael Callahan (September 3, 1941 – February 8, 2012) was an American politician from Annapolis, Maryland.  A native of Baltimore, Callahan had been a mayor of Annapolis and a director of the Recreation and Parks Department of Anne Arundel County, Maryland.  He ran unsuccessfully in the Democratic primary for Anne Arundel County Executive in 2006.  The general election winner, Republican John R. Leopold, appointed Callahan chief administrative officer of Anne Arundel County, a position he held at the time of his death.

John Callahan's Quads!: John Callahan's Quads!  is a Canadian-Australian co-production cartoon, based upon work of John Callahan.  The show aired on Canada's Teletoon, on Australia's SBS, and in Latin America on Locomotion and then on Adult Swim.  It is noted for being one of the first shows animated completely using Macromedia Flash software.

John Callahan (Wisconsin politician): John Callahan (December 16, 1865 – May 10, 1956) was an American educator.

Pelswick: Pelswick is an animated television series co-produced by Nelvana Limited and Suzhou Hong Ying Animation Corporation Limited in association with The Canadian Broadcasting Corporation and Nickelodeon.  The series is about a teenage boy who uses a wheelchair, emphasizing that he lived a normal life.  It was based on the books created by John Callahan.  It aired during "Nick on CBS" beginning on September 14, 2002, and ended in November of that year.  Unlike most Nicktoons, "Pelswick" is not rerun on NickSplat.

Lost Dogs and Mixed Blessings: Lost Dogs and Mixed Blessings is the 12th studio album by American folk singer John Prine, released in 1995.  The cover artwork is by John Callahan.

Supporting paragraphs: John Callahan's Quads! John Callahan (cartoonist)
Answer: Portland, Oregon