Can CDs or Treasury bills work for part of my emergency savings?

Yes, for the portion you are unlikely to need immediately. Certificates of deposit and Treasury bills typically pay a bit more than savings accounts but lock your money for a set term. To keep access, build a ladder: split the money across CDs or T-bills maturing at staggered dates, such as every three months, so something is always coming due. Treasury bills, backed by the U.S. government and bought at treasurydirect.gov or through a brokerage, are state-tax-free on their interest, which helps if you live in a high-tax state. The catch is that breaking a CD early usually costs several months of interest, so never put your instant-access tier into one. Keep enough in liquid savings that you would never be forced to break a CD in a pinch.