Source: httpsmilla4tumblrcom-smilla4blogs.blogspot.com [sic]
Small towns in Maine such as this one served as the backdrop to King's childhood years.
King grew up during the Cold War era. The outlook at the time was full of apprehension regarding the future, and many works written at the time reflected such a view. George Orwell's 1984 details a dystopian future where opposing the regime – even in thought – is a crime punishable by death. Political dystopia is used by King in many of his works, notably The Long Walk and The Running Man, which were both published under a pseudonym.
At the same time as the Cold War, the United States was undergoing a wide variety of social changes, such as the Civil Rights movement, the Sexual revolution, counterculture, etc. Shifting ideals of society and equality were the subject of many tensions along this time period. The example of social issues comes up repeatedly in King's stories, such as It, in which crimes motivated by prejudice serve as the modus operandi of a demon living in a small town.
King – like many of his contemporaries – tries to capture elements of 20th century Americana in his works. References to American popular culture are present in all of his works – from his earliest to his most recent.
Additionally, as a result of his upbringing in New England, Stephen King has popularized the horror trope of a small-town setting. Many of King's works take place in small-town Maine, where the quiet, idyllic life of suburbia sharply contrasts with the gruesome events that inevitably occur there.
Richard Bachman's supposed author photo. The photo was actually of King's literary agent's insurance agent. Image source: Wikimedia