Federal government monthly outlays, documented in the Treasury's Monthly Treasury Statement (MTS), provide a comprehensive view of U.S. government spending patterns. These expenditures fall into three main categories: Mandatory spending (approximately 65%) includes legally-required programs like Social Security (the largest single expenditure), Medicare, Medicaid, veterans' benefits, and income security programs. Discretionary spending (roughly 27%) encompasses annually-budgeted items, with defense spending representing about half of this category, including military personnel costs, weapons procurement, and R&D. The remainder covers domestic programs like education, transportation infrastructure, and scientific research. Interest payments on the national debt (approximately 8%) vary with debt levels and interest rates, representing a growing portion of federal spending. The Congressional Budget Office (CBO) projects these interest costs will become one of the fastest-growing budget components due to rising debt levels and interest rates. Understanding these outlays is crucial for analyzing fiscal policy, budget priorities, and long-term financial sustainability.