The setting of the Peanuts comic strip is a matter of dispute amongst its fans.
In the early 1960s, a character named 5 was introduced whose last name, 95472, was the zip code of Sebastopol, California (where Charles Schulz's office was located). However, there is snow during the winter in the children's hometown, suggesting it may be near St. Paul or Minneapolis, where Charles Schulz grew up.
There is a comic strip with Linus hugging a sign that said in bold letters, "Pinetree Corners." Schulz stated that he put it in as an "inside joke" and said that was not where the characters lived.
In a comic strip from February 15, 1957 it is stated that the characters live in Hennepin County, which is in Minnesota. In the strip from June 9, 1955 an embarrassed Schroeder admits that he always thought that Beethoven was a native of Minnesota. It only makes sense for him to assume his idol was from his home state.
The ending of the segment "Yuletide Greetings from Linus" in the 2002 special Charlie Brown's Christmas Tales has Lucy giving Linus back an envelope with the card that he wrote to the a new girl in his school in it because the address he wrote did not exist. If one looks carefully at the envelope, the writing reads "Sparkyville (in nondescript writing), USA." "Sparky" was a nickname given to Schulz at an early age, so it may be possible that their town is named after him.
The Peanuts specials in the 1960's opened with an overhead shot of St. Paul, the first movie A Boy Named Charlie Brown opened with a shot of Minneapolis. The specials in the 1970s and 1980s (with the captive animation), kept on suggesting the setting was in California (the specials of that era and A Boy Named Charlie Browns sequel Snoopy Come Home were set in Santa Rosa as stand-ins for Minneapolis).
It can be argued that Peanuts has greater associations with Santa Rosa, California (where Charles Schulz's new office was) than Minneapolis or St. Paul (especially after Camp Snoopy in that area changed sponsors).