Supporting and investing in the integration of immigrants and their children is critically important to US society. Successful integration contributes to the nation's economic vitality, its civic and political health, and its cultural diversity. But although the United States has a good track record on immigrant integration, outcomes could be better. A national, coherent immigrant integration policy infrastructure is needed. This infrastructure can build on long-standing partnerships between civil society and US public institutions. Such partnerships, advanced under Republican- and Democratic-led administrations, were initially established to facilitate European immigrants' integration in large American cities, and later extended to help refugees fleeing religious persecution and war. In the twenty-first century, we must expand this foundation by drawing on the growing activism by cities and states, new civil society initiatives, and public-private partnerships that span the country. A robust national integration policy infrastructure must be vertically integrated to include different levels of government and horizontally applied across public and private sector actors and different types of immigrant destinations. The resultant policy should leverage public-private partnerships, drawing on the energy, ideas, and work of community-based nonprofit organizations as well as the leadership and support of philanthropy, business, education, faith-based, and other institutions. A new coordinating office to facilitate interagency cooperation is needed in the executive branch; the mandate and programs of the Office of Refugee Resettlement need to be secured and where possible expanded; the outreach and coordinating role of the Office of Citizenship needs to be extended, including through a more robust grant program to community-based organizations; and Congress needs to develop legislation and appropriate funding for a comprehensive integration policy addressed to all, and not just humanitarian immigrants. The federal investments in immigrant and refugee integration we propose are a big ask for any administration; they seem especially unlikely under the Trump administration, whose efforts focus on enforcement and border control, targeting undocumented and legal immigrants alike. Yet immigrant integration is not and should not be a partisan issue. Federal politicians across the political spectrum need to realize, as many local officials and a large segment of the public already do, that successful immigrant integration is a win-win for everybody. When immigrants have more opportunities to learn English, to improve their schooling and professional training, to start businesses, and to access citizenship, we all benefit. A majority of the American public supports immigrant integration, from proposals for learning English to a path to citizenship for undocumented immigrants. Local and state governments are setting up initiatives to promote integration. If the federal government will not act, cities, states, and civil society organizations must continue to work together to build an integration infrastructure from the bottom up.