What barriers block immigrants from applying for citizenship and what interventions can help immigrants surmount these barriers? We partnered with the City of Zurich, Switzerland, to answer these questions by administering a randomized control trail on informational outreach campaigns. From a population of 10,000 citizenship-eligible immigrants, we randomly assigned 5,000 of them to receive a letter from the City with information about naturalization and encouragement to apply in October 2019; the other 5,000 will receive the letter in April 2020. In between these two dates, we invite the entire population to participate in a two-wave survey that measures their beliefs and knowledge about naturalization and their integration levels more generally. The findings from this study will contribute to literature on citizenship, on immigrant integration, and on the effectiveness of informational nudges on political participation more broadly.