Executive Summary In October 2017, the Center for Migration Studies of New York (CMS) initiated a study to map the stateless population in the United States. This study sought to: Develop a methodology to estimate the US stateless population; Provide provisional estimates and profiles of persons who are potentially stateless or potentially at risk of statelessness in the United States; Create a research methodology that encouraged stateless persons to come forward and join a growing network of persons committed to educating the public on and pursuing solutions to this problem; and Establish an empirical basis for public and private stakeholders to develop services, programs, and policy interventions to prevent and reduce statelessness (UNHCR 2014g, 6), and to safeguard the rights of stateless persons ( UNHCR 2014d ). This report describes a unique methodology to produce estimates and set forth the characteristics of US residents who are potentially stateless or potentially at risk of statelessness. The methodology relies on American Community Survey (ACS) data from the US Census Bureau, supplemented by very limited administrative data on stateless refugees and asylum seekers. 1 As part of the study, CMS developed extensive, well-documented profiles of non–US citizen residents who are potentially stateless or potentially at risk of statelessness. It then used these profiles to query ACS data to develop provisional estimates and determine the characteristics of these populations. The report finds that the population in the United States that is potentially stateless or potentially at risk of statelessness is larger and more diverse than previously assumed, albeit with the caveat that severe data limitations make it impossible to provide precise estimates of this population. Stateless determinations require individual screening, which the study could not undertake. Individuals deemed potentially stateless or potentially at risk of statelessness in this report may in fact have been able to secure nationality in their home countries or in third countries. They may also be on a path to citizenship in the United States, although nobody in CMS’s estimates had yet to obtain US citizenship. According to CMS’s analysis, roughly 218,000 US residents are potentially stateless or potentially at risk of statelessness. These groups live in all 50 states, 2 with the largest populations in California (20,600), New York (18,500), Texas (15,200), Ohio (13,200), Minnesota (11,200), Illinois (8,600), Pennsylvania (8,200), Wisconsin (7,300), Georgia (6,600), and Virginia (6,500). The report recommends ways to improve data collection and, thus, develop better estimates in the future. It also lifts up the voices and challenges of stateless persons, and outlines steps to reduce statelessness and safeguard the rights of stateless persons in the United States. As it stands, the paucity of reliable federal data on the stateless, the lack of a designated path to legal status for them under US law, and the indifference of government agencies contribute to the vulnerability and isolation of these populations.