Who can be adopted?

In this article you will know Who can be adopted?

General requirements state-by-State

All states, the District of Columbia and the u.s. territories permit the adoption of a child.
Three states (Colorado, Indiana, and Rhode Island), American Samoa, and the Northern Mariana Islands specify that the adoptee must be under 18 years of age.
Four states (Connecticut, Delaware, Montana, Wisconsin, and wyoming), American Samoa, and Guam specify in their legislation that the child must be legally free for adoption.
Six states (Arizona, Colorado, South Carolina, Texas, Wisconsin, and Wyoming), American Samoa, and the Virgin Islands require that the child to be adopted is present in the state at the time of the adoption petition.
Iowa requires that the child has resided for a minimum period of 180 days in the home of the potential parents.

Approximately 26 states and the District of Columbia allow the adoption of any person, regardless of their age.
Rhode Island, American Samoa, and the Northern Mariana Islands allow you to apply to the court for the adoption of people over 18 years but under the age of 21.
Nevada specifies that the adult to be adopted must be younger than the adoptive father.
West Virginia allows residents of the state to adopt an adult.

Alabama restricts the adoption of adults to persons who are permanently and totally disabled, or who suffer mental retardation.
Ohio allows adoption of an adult only when the person is permanently disabled, suffers mental retardation, is a stepchild or a person who is nursed when he was a minor.
Idaho, Illinois, and South Dakota requesting that the adoptive parent maintain a relationship with the adult to adopt for a period of between six months and two years.
Virginia allows you to adopt a step-child(a) adult, or to a niece or nephew), always and when the person adopting resides in the home of the adoptive parent for at least three months prior to meeting the age of majority, and is at least fifteen years younger than the adoptive parent.