The Oklahoma Taxpayer and Citizen Protection Act (House Bill 1804) went into effect on November 1, 2007. House Bill (HB) 1804, is among the most far-reaching of the anti-immigrant laws enacted at the state level and is composed of broad provisions that have the potential to affect all aspects of life in Oklahoma for unauthorized immigrants, including where they live, how they move from place to place, what services they receive from both public and private agencies, and how they are handled when they come into contact with the law enforcement system. The Urban Institute examined the effects of HB 1804 to better understand the implications of these provisions for immigrant families with children.