My 1099-DIV does not have a Box 2a. It jumps from Box 1b to Box 3. What should I enter for Box 2a?

Box 2(a) on a form 1099-DIV is for capital gain distributions. It is not uncommon to not have any of those, so if your 1099-DIV does not have a box entry for that, just don't enter anything for box 2(a) when you make your 1099-DIV entry in TurboTax.