It is vastly easier to apply for the SSN at the hospital at time of birth. If you don't, there are many non-trivial hurdles to jump through later[0]: At a Soc

It is vastly easier to apply for the SSN at the hospital at time of birth. If you don't, there are many non-trivial hurdles to jump through later[0]: At a Social Security office: If you wait to apply for your child’s number, you must: • Complete an application for a Social Security card; and • Show us original documents proving your child’s: — U.S. citizenship; — Age; and — Identity. • Show us documents proving your identity and your relationship to the child. [0] https://www.ssa.gov/pubs/EN-05-10023.pdf https://www.ssa.gov/pubs/EN-05-10023.pdf