Where It All Goes Down
Early 1900's America, the Kitchen of Wright Farmhouse
Turn of the 20th century, America
It's a wee bit tricky (because Glaspell doesn't give us an exact year) but we do know the play was first performed in 1916. So we'll go ahead and assume it's set somewhere around then, but probably a little earlier. The thing that's totally clear is that this play is set in a time in America when women got way less respect than they do now.
Not that we don't still have room to improve, but women didn't even have the right to vote when Trifles was first performed. Suffrage didn't come around till 1920 when, after years of struggle, the feminist movement finally shoved the 19th Amendment through Congress.
The thing that's important to realize is that the slew of sexist comments from the menfolk in the play represent the attitude of most men in the country. The play's ladies aren't the victims of a few random jerks; they're the victims of a whole society of jerks who don't even realize how jerky they are… which sort of makes them even bigger jerks.
The Wright Farmhouse
Mrs. Hale gives us the details on the Wright house here:
Mrs. Hale: I stayed away because it weren't cheerful [...]. I've never liked this place. Maybe because it's down in a hollow and you don't see it from the road. I dunno what it is but it's a lonesome place and always was. (101)
Yeah, that doesn't sound like anybody's dream home. We can totally see why Mrs. Wright might've gone a little nuts in this place. It's totally isolated, because it's in a hollow (which is like a little valley).
Mrs. Wright had zero contact with anybody except for her jerk of a husband; she couldn't even wave at people who were cruising by on the road. It's not hard to get how Mrs. Wright might've felt like a bird in a cage.
The Kitchen
The only part of the Wright house that we actually see on stage is the kitchen, which doesn't sound so nice. The very first line of the stage directions tells us straight up that the kitchen is "gloomy" (1). Ugh, that's incredibly depressing, considering that Mrs. Wright probably had to spend most of her time in that kitchen.
On top of being generally gloomy, the kitchen is also full of signs of "incompleted work" (1). There are dishes in the sink, a filthy dishtowel, dirty rags, and a random loaf of stale bread. Later we also learn that one of the cabinets is full of sticky, oozing preserves because Mrs. Wright's jam jars burst over night.
The men see the dirty, gloomy kitchen as a sign that Mrs. Wright was a bad housekeeper, which in their mind translates to her being a bad woman in general. They're so oblivious to the female perspective that they don't even seem to take into account the fact that Mrs. Wright had to sort of leave things as they were when she was hauled off to jail. Kind of hard to keep things tidy at home when you're... not there.
Probably the most important thing to think about here is that the kitchen is symbolic of women in general. In this time period especially, the kitchen was thought of as the woman's place. The men are so dismissive of it that they don't even bother to look for clues there, which is pretty bizarre since they're investigating a crime committed by a woman.
The Sheriff even has this slightly hilarious line: "Nothing here but kitchen things" (26). (Oh, classic Sheriff.) The irony of this line pokes us in the face later when it's in the kitchen that Mrs. Hale and Mrs. Peters later find the clue for which the men are looking. Sorry, Sheriff. Guess you should've paid a little more attention to "kitchen things."