The Innovation Fund Act establishes a federal grant program to reward cities, counties, and other local governments that successfully increase their housing supply, particularly affordable and "attainable" housing for low- and moderate-income households. The Department of Housing and Urban Development must award at least 25 annual grants ranging from $250,000 to $10 million to eligible communities, with the program prioritizing those using innovative policies like zoning reforms, eliminating parking requirements, and streamlining building regulations. Grant recipients can use funds for community development activities, infrastructure improvements, or housing expansion initiatives, and the bill authorizes $200 million annually from fiscal years 2027 through 2031, adjusted for inflation. The bill applies to metropolitan areas, counties, local governments, and tribal nations that demonstrate housing supply growth, and the legislation explicitly protects local control by preventing the federal government from mandating or overriding local zoning decisions.