The inaugural ball is considered a formal event. Your invitation denotes appropriate attire as Black Tie, Black Tie Preferred, or Black Tie Optional. Black Tie indicates that tuxedos are preferred, Black Tie Preferred and Black Tie Optional indicate that men can choose to wear either a tuxedo or a dark suit with a tie.
For women, the choices are many. This is great in that there are many style options from which to choose. This can also be a tad bit intimidating for the same reason. Having said that, one key thing to keep in mind is that since the inaugural ball is a formal event, you will want to pull out all the stops. If you are unsure about what length your dress should be, rest assured that a floor length gown is appropriate. A simple, strapless, well-fitted, elegant floor-length gown with appropriate embellishment is always a classic choice that will get you noticed in a good way. If you are not comfortable with wearing a strapless gown, there are many beautiful dresses available to you that have sleeves to suit your taste. Since the dress is understated, you have some leeway with your accessory choices. You could wear beautiful silver or white gold drop and dangle earrings or a statement necklace. For footwear you could choose a mid to high-heeled pump in black, or you could wear a mid to high-heeled sparkly, strappy sandal.
For those who choose a look that is a bit edgier, there are many choices available. For instance you may choose a gown that has color like an electric blue or a lipstick red in a satin fabric. It is also important to note that the rules regarding or requiring that a floor-length gown be worn by women no longer apply. Just remember if you are going to wear a dress that has print or bold color to choose something with clean lines. This look is a statement within itself, so you will want to take care when making jewelry selection. Choosing simple diamond stud or pearl earrings or an understated necklace or wrist cuff will suffice. If you wear the dangle-drop earrings with this look, you run the risk of looking over-dressed. Make sure that your shoes are elegant. You cannot go wrong with a well-healed pump that coordinates with your dress. It is also important to note here that the rules that required women to wear floor-length gowns to inaugural balls no longer applies. So, if you would rather, a cocktail-length dress is acceptable.
Let us not forget about outerwear as the temperatures are sure to be quite cold. It is important to wear a coat that will keep you sufficiently warm. It is advisable that you keep your coat with you and not check it as this will save you time by not having to wait in the coat check line when the crowds start to thin out.