The town where the March and Laurence families live is never given a name in the novel, but it's clearly somewhere in New England and loosely based on Concord, Massachusetts, where Louisa May Alcott's family lived all her life. Although the March sisters will at times travel the globe – Jo goes to New York, while her sister Amy embarks on a European tour – they always come back to the family home in the northeastern United States. We realize just how proud the March girls really are of their American heritage when Laurie hosts a picnic for some visiting British friends – their pride in the democratic ideals of independence and advancement through hard work is obvious. Being in New England in the mid-nineteenth century also means they're close to the philosophical community of the Transcendentalists – you know, people like Emerson and Thoreau. Mr. March, like the real-life Bronson Alcott on whom he is based, is one of these enlightened forward-thinking men.
There are a lot of clues to the time frame in which the book takes place. The first chapter begins at Christmastime in the middle of the Civil War; it's not clear exactly what year, but sometime in the early 1860s. The first volume of the novel – the original Little Women, which ends with Chapter 23 – spans one year, from Christmas to the next Christmas, and ends with the war still going. Over the course of this first part, Jo goes from being fifteen to being sixteen.
The second volume of the novel, beginning with Chapter 24 and originally titled Good Wives, starts three years later. Jo seems to be nineteen, and this part of the novel spans the events of about six years – Jo is almost 25 when she becomes engaged to Mr. Bhaer, and they marry a year later, when she's presumably almost 26. The novel ends with a birthday party for Marmee five years after Jo's wedding – so Jo is just about 30, going on 31. Take-away fact: from the beginning of the first chapter to the end of the last chapter, the novel covers around fifteen years, but the last five years are summarized really fast at the very end, and another three years get skipped in the middle.
Why does this timing matter? Well, it's long – a broad swath of years which gives us a picture of the March girls from childhood through to maturity. This wide-angle view is typical of the nineteenth-century novel, which often gives a complete picture of an individual, a family, or an entire society. By contrast, the Modernist novel in the early twentieth century has a narrower focus – think of James Joyce's Ulysses, which takes place in a single day! If the fifteen years covered by Little Women aren't enough for you, then you can read the sequels Little Men and Jo's Boys, which take Jo into her fifties!