This is typical of family photos taken in communities that could not support dedicated commercial studios. The platform rests on roughly shaped beams like a porch but it seems too shallow with no evidence of a protective roof; the wainscoting and plastered wall do not look like typical exterior construction, yet the light seems too bright and even to be an interior, so I am not at all sure where they are.
We are also left at sea regarding the clothing period; most resources on fashion focus on just that – the fashionable attire of upper classes; what people wore in rural or small town America obviously was less tied to the latest thing. This family of nine is very nicely dressed and conscious of presenting themselves well. All of the girls are in pigtails tied with bows; the two on the end might be fraternal twins as they are dressed identically including their brooches; the little boy is wearing what we would call a blouse, not uncommon for the times (we may wonder if this went on until they rebelled or got into fights in defense of their gender); the middle son appears to have been stuck with the hand-me-downs as is often the lot of fast-growing middlers; the older son cuts a manly figure, the only one with a hat. Mom has on her Sunday best. What strikes me is their dark eyes.
The photo came from Oklahoma. I will guess last years of the 19th century – only a guess.