A number of factors will determine how long it takes to get a divorce. Some of these are legal requirements, which vary by state.
Residency requirements. This is the length of time one or both parties must be a resident of the state. Some states this wont matter but others could require one year.
Separation requirements. In some states, you and your spouse must be living separately for a certain time period which could be up to three years in order to obtain a divorce.
Waiting periods. A number of states require that a certain amount of time passes after
filing for divorce before you can schedule a court hearing or entering a final judgment. Some waiting periods can be up to 90 days.
Other things to consider would be mediation of issues in dispute, marriage counseling, etc, that some states may require In addition to there legal requirements, there are other factors that y affect the amount of time it takes, including how long it takes to have your spouse served with divorce papers.