In which state do I file for allocation of parental responsibilities?
The general rule is that Colorado state courts have authority to hear a custody case if CO is considered your child's “home state”.1 A child's “home state” is generally the state where the child has most recently lived with a parent (or a person acting as a parent) for at least 6 consecutive months. In the case of a child less than 6 months old, the “home state” is the state where the child has lived from birth. A short, temporary absence from the state does not change anything.
If you and your child recently moved to a new state, generally you cannot file for custody in that new state until you have lived there for at least six months. Until then, either you or the other parent can start a custody action in the state in which your child most recently lived for at least six months.
Example: If a family has lived in MT for one year and then one parent moved to CO with the children and filed in CO after living there for only four months, CO is still the home state. CO would likely not have jurisdiction (power) over the custody of the children.
There are exceptions to the “home state rule.” For more information, please see the following section, What are the exceptions to the "home state” rule?
1 C.R.S. § 14-13-102(7)(a)